U.S. patent application number 11/773051 was filed with the patent office on 2013-12-26 for polyurea/polythiourea coatings.
The applicant listed for this patent is Nina Bojkova, John R. Gilmore, Paul P. Greigger, Thomas R. Hockswender, Gregory J. McCollum, Chandra B. Rao, Howard Senkfor. Invention is credited to Nina Bojkova, John R. Gilmore, Paul P. Greigger, Thomas R. Hockswender, Gregory J. McCollum, Chandra B. Rao, Howard Senkfor.
Application Number | 20130344340 11/773051 |
Document ID | / |
Family ID | 39720600 |
Filed Date | 2013-12-26 |
United States Patent
Application |
20130344340 |
Kind Code |
A1 |
Senkfor; Howard ; et
al. |
December 26, 2013 |
POLYUREA/POLYTHIOUREA COATINGS
Abstract
Polyurea/polythiourea compositions comprising the reaction
product of a first component comprising isocyanate and a second
component comprising an amine, wherein the first component further
comprises an isocyanate functional polythioether-polyurethane
and/or polythiourethane, and/or the second component further
comprises an amine/hydroxy functional polythioether, are disclosed.
Methods for using the coating, and substrates coated therewith, are
also disclosed.
Inventors: |
Senkfor; Howard; (South
Euclid, OH) ; Hockswender; Thomas R.; (Gibsonia,
PA) ; Bojkova; Nina; (Monroeville, PA) ;
Greigger; Paul P.; (Cranberry Township, PA) ;
McCollum; Gregory J.; (Gibsonia, PA) ; Gilmore; John
R.; (Valencia, CA) ; Rao; Chandra B.;
(Valencia, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Senkfor; Howard
Hockswender; Thomas R.
Bojkova; Nina
Greigger; Paul P.
McCollum; Gregory J.
Gilmore; John R.
Rao; Chandra B. |
South Euclid
Gibsonia
Monroeville
Cranberry Township
Gibsonia
Valencia
Valencia |
OH
PA
PA
PA
PA
CA
CA |
US
US
US
US
US
US
US |
|
|
Family ID: |
39720600 |
Appl. No.: |
11/773051 |
Filed: |
July 3, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11744259 |
May 4, 2007 |
|
|
|
11773051 |
|
|
|
|
60797985 |
May 5, 2006 |
|
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Current U.S.
Class: |
428/419 ;
524/500 |
Current CPC
Class: |
Y10T 428/31551 20150401;
C08G 18/3234 20130101; C09D 175/02 20130101; C08G 18/12 20130101;
C08G 18/10 20130101; C08G 18/3876 20130101; C08G 18/12 20130101;
Y10T 428/31533 20150401; C08G 18/52 20130101; C08G 18/12 20130101;
C08G 18/325 20130101; C08G 18/4854 20130101; C08G 18/792 20130101;
C09D 181/00 20130101; C08G 18/10 20130101; C08G 18/10 20130101;
C08G 18/12 20130101; C08G 18/10 20130101; C08G 18/7837 20130101;
C08G 18/6685 20130101; C08G 18/792 20130101; C08G 18/6685 20130101;
C08G 18/7837 20130101 |
Class at
Publication: |
428/419 ;
524/500 |
International
Class: |
C09D 181/00 20060101
C09D181/00; C09D 175/02 20060101 C09D175/02 |
Claims
1. A coating composition comprising polyurea and polythiourea
formed from a reaction mixture comprising: a first component
comprising (i) an isocyanate selected from one or more of
isophorone diisocyanate (IPDI), cyclohexylene diisocyanate,
4,4'-methylenedicyclohexyl diisocyanate (H.sub.12MDI),
tetramethylxylyl diisocyanate,
OCN--C(CH.sub.3).sub.2--C.sub.6H.sub.4C(CH.sub.3).sub.2--NCO,
1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,
1,6-hexamethylene diisocyanate (HMDI), 1,7-heptamethylene
diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate,
2,4,4-trimethylhexamethylene diisocyanate, 1,10-decamethylene
diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, phenylene
diisocyanate, toluene diisocyanate (TDI), xylene diisocyanate,
1,5-naphthalene diisocyanate, chlorophenylene 2,4-diisocyanate,
bitoluene diisocyanate, dianisidine diisocyanate, tolidine
diisocyanate, alkylated benzene diisocyanates, methylenediphenyl
diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, the
uretdione of 1,6-hexamethylene diisocyanate, the biuret of
1,6-hexanediisocyanate, the isocyanurate of 1,6-hexanediisocyanate,
and the isocyanurate of isophorone diisocyanate; and (ii) an
isocyanate functional compound comprising a
polythioether-polyurethane and/or polythiourethane; wherein at
least 1 percent by weight of the first component comprises at least
one polyisocyanate monomer; and a second component comprising an
amine and an amine/hydroxy functional polythioether that is
different from the amine, wherein the amine/hydroxy functional
polythioether comprises an amine-functional reaction product of an
epoxy functional polythioether and a polyamine.
2-5. (canceled)
6. The coating composition of claim 1, wherein the isocyanate
functional compound comprises a polythiourethane reaction product
of a thiol-functional polythioether and an isocyanate functional
compound.
7. The coating composition of claim 1, wherein the isocyanate
functional compound comprises a polythioether-polyurethane reaction
product of a hydroxy-functional polythioether and an isocyanate
functional compound.
8. (canceled)
9. A method for coating a substrate comprising: applying to at
least a portion of the substrate the coating composition of claim
1.
10. A substrate coated at least in part with the coating of claim
1.
11. The substrate of claim 10, wherein the substrate comprises at
least a portion of a vehicle.
12. The substrate of claim 11, wherein the substrate comprises a
truck bed.
13. The substrate of claim 10, wherein the substrate comprises at
least a portion of a building structure.
14. A coating composition comprising polyurea and polythiourea
formed from a reaction mixture comprising: a first component
comprising an isocyanate selected from one or more of isophorone
diisocyanate (IPDI), cyclohexylene diisocyanate,
4,4'-methylenedicyclohexyl diisocyanate (H.sub.12MDI),
tetramethylxylyl diisocyanate,
OCN--C(CH.sub.3).sub.2--C.sub.6H.sub.4C(CH.sub.3).sub.2--NCO,
1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,
1,6-hexamethylene diisocyanate (HMDI), 1,7-heptamethylene
diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate,
2,4,4-trimethylhexamethylene diisocyanate, 1,10-decamethylene
diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, phenylene
diisocyanate, toluene diisocyanate (TDI), xylene diisocyanate,
1,5-naphthalene diisocyanate, chlorophenylene 2,4-diisocyanate,
bitoluene diisocyanate, dianisidine diisocyanate, tolidine
diisocyanate, alkylated benzene diisocyanates, methylenediphenyl
diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, the
uretdione of 1,6-hexamethylene diisocyanate, the biuret of
1,6-hexanediisocyanate, the isocyanurate of 1,6-hexanediisocyanate,
and the isocyanurate of isophorone diisocyanate; wherein at least 1
percent by weight of the first component comprises at least one
polyisocyanate monomer; and a second component comprising an amine
and an amine/hydroxy functional polythioether different from the
amine, wherein the amine/hydroxy functional polythioether comprises
an amine-functional reaction product of an epoxy functional
polythioether and a polyamine.
15-16. (canceled)
17. The coating composition of claim 14, wherein the first
component and the second component can be applied to a substrate at
a volume mixing ratio of 1:1.
18-21. (canceled)
22. A method for coating a substrate comprising: applying to at
least a portion of the substrate the coating composition of claim
14.
23. A substrate coated at least in part with the coating of claim
14.
24. The substrate of claim 23, wherein the substrate comprises at
least a portion of a vehicle.
25. The substrate of claim 24, wherein the substrate comprises a
truck bed.
26. The substrate of claim 23, wherein the substrate comprises at
least a portion of a building structure.
27-37. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a Continuation-In-Part (CIP) of
U.S. patent application having Ser. No. 11/744,259, filed on May 4,
2007 and pending, which claims priority to U.S. Provisional Patent
Application 60/797,985 filed on May 5, 2006, and which are hereby
incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention is directed to a coating composition
comprising polyurea and polythiourea.
BACKGROUND OF THE INVENTION
[0003] Coating compositions comprising polyureas are used in a wide
variety of industries such as automotive, watercraft, aircraft,
industrial, construction, military, recreational equipment
including sports equipment and the like. In these industries,
considerable efforts have been made to develop coating compositions
that will impart the desired properties to the substrate or article
being coated. For example, coatings are used to protect against
damage due to corrosion, abrasion, impact, chemicals, ultraviolet
light, flame, heat, and/or other environmental exposure. In
addition to any of these functional properties, coatings can also
be used for decorative purposes.
[0004] Sulfur-containing compounds are known to be well suited for
use in aerospace sealants due to their fuel resistant nature upon
crosslinking. For example, polysulfide sealants can offer high
tensile strength, high tear strength, thermal resistance and
resistance to high ultraviolet light. Such sealants can also offer
resistance to fuel and maintain their adhesion upon exposure to
fuel.
[0005] Polyureas are generally formed by reacting amines and
isocyanates. The use of amines such as polyamines as crosslinkers
or "curatives" is well known. For example, amines are known to
crosslink with isocyanates to form urea compounds. Similarly,
sulfur-containing compounds are known to crosslink with isocyanates
to form thiourea compounds. The use of sulfur-containing compounds
in a polyurea coating, however, has been difficult due to the high
viscosity and odor of the sulfur-containing compounds.
Combinations, however, would be desirable to provide optimum
properties.
SUMMARY OF THE INVENTION
[0006] The present invention is directed to a coating composition
comprising polyurea and polythiourea formed from a reaction mixture
comprising a first component comprising an isocyanate and an
isocyanate functional polythioether-polyurethane and/or
polythiourethane, and a second component comprising an amine.
[0007] The present invention is also directed to a coating
composition comprising polyurea and polythiourea formed from a
reaction mixture comprising a first component comprising an
isocyanate, and a second component comprising an amine and an
amine/hydroxy functional polythioether.
[0008] The present invention is also directed to a coating
composition comprising polyurea and polythiourea formed from a
reaction mixture comprising a first component comprising an
isocyanate and an isocyanate functional polythioether-polyurethane
and/or polythiourethane, and a second component comprising an amine
and an amine/hydroxy functional polythioether.
[0009] The present invention is further directed to methods for
coating a substrate using such coatings, and substrates coated
thereby.
DETAILED DESCRIPTION OF THE INVENTION
[0010] The present invention is directed to a coating composition
comprising polyurea and polythiourea formed from a reaction mixture
comprising a first component comprising isocyanate ("isocyanate
component"), a second component comprising an amine ("amine
component"), and a sulfur-containing compound in the first and/or
second component. The first component further comprises an
isocyanate functional polythioether-polyurethane and/or
polythiourethane, and/or the second component further comprises an
amine/hydroxy functional polythioether. The amine component may be
referred to herein as a "curative" because it will react or cure
with the isocyanate to form a polyurea and/or a polythiourea. In
certain embodiments, the ratio of equivalents of isocyanate groups
to equivalents of amine/mercaptan groups is greater than 1 and the
isocyanate component and the amine component can be applied to a
substrate at a volume mixing ratio of 1:1. The terms "mercaptan"
and variants thereof and "thiol" and variants thereof are used
interchangeably herein.
[0011] As used herein, the term "isocyanate" includes unblocked
compounds capable of forming a covalent bond with a reactive group
such as a hydroxyl, mercaptan or amine functional group. Thus,
isocyanate can refer to "free isocyanate", which will be understood
to those skilled in the art. In alternate non-limiting embodiments,
the isocyanate of the present invention can be monofunctional
containing one isocyanate functional group (NCO) or the isocyanate
used in the present invention can be polyfunctional containing two
or more isocyanate functional groups (NCOs).
[0012] Suitable isocyanates for use in the present invention are
numerous and can vary widely. Such isocyanates can include those
that are known in the art. Non-limiting examples of suitable
isocyanates can include monomeric and/or polymeric isocyanates. The
polyisocyanates can be selected from monomers, prepolymers,
oligomers, or blends thereof. In an embodiment, the polyisocyanate
can be C.sub.2-C.sub.20 linear, branched, cyclic, aromatic, or
blends thereof.
[0013] Suitable isocyanates for use in the present invention may
include but are not limited to isophorone diisocyanate (IPDI),
which is 3,3,5-trimethyl-5-isocyanato-methyl-cyclohexyl isocyanate;
hydrogenated materials such as cyclohexylene diisocyanate,
4,4'-methylenedicyclohexyl diisocyanate (H.sub.12MDI); mixed
aralkyl diisocyanates such as tetramethylxylyl diisocyanates,
OCN--C(CH.sub.3).sub.2--C.sub.6H.sub.4C(CH.sub.3).sub.2--NCO;
polymethylene isocyanates such as 1,4-tetramethylene diisocyanate,
1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate
(HMDI), 1,7-heptamethylene diisocyanate, 2,2,4- and
2,4,4-trimethylhexamethylene diisocyanate, 1,10-decamethylene
diisocyanate and 2-methyl-1,5-pentamethylene diisocyanate; and
mixtures thereof.
[0014] Non-limiting examples of aromatic isocyanates for use in the
present invention may include but are not limited to phenylene
diisocyanate, toluene diisocyanate (TDI), xylene diisocyanate,
1,5-naphthalene diisocyanate, chlorophenylene 2,4-diisocyanate,
bitoluene diisocyanate, dianisidine diisocyanate, tolidine
diisocyanate, alkylated benzene diisocyanates,
methylene-interrupted aromatic diisocyanates such as
methylenediphenyl diisocyanate, 4,4'-isomer (MDI) including
alkylated analogs such as 3,3'-dimethyl-4,4'-diphenylmethane
diisocyanate, polymeric methylenediphenyl diisocyanate and mixtures
thereof.
[0015] In a non-limiting embodiment, polyisocyanate monomer may be
used. It is believed that the use of a polyisocyanate monomer
(i.e., residual-free monomer from the preparation of prepolymer)
may decrease the viscosity of the polyurea/polythiourea composition
thereby improving its flowability, and may provide improved
adhesion of the polyurea/polythiourea coating to a previously
applied coating and/or to an uncoated substrate. For example, the
coatings that have been previously applied to a substrate can
comprise functional groups (e.g. hydroxy groups) that are reactive
with isocyanates, thereby enhancing adhesion of this coating to the
polyurea/polythiourea composition of the present invention applied
over this coating. A lower viscosity polyurea/polythiourea
composition may also remain in a "flowable" state for a longer
period of time as compared to a comparable composition having a
higher viscosity. In alternate embodiments of the present
invention, at least 1 percent by weight, or at least 2 percent by
weight, or at least 4 percent by weight of the isocyanate component
comprises at least one polyisocyanate monomer.
[0016] In a further embodiment of the invention, the isocyanate can
include oligomeric polyisocyanates including but not limited to
dimers, such as the uretdione of 1,6-hexamethylene diisocyanate,
trimers, such as the biuret and isocyanurate of
1,6-hexanediisocyanate and the isocyanurate of isophorone
diisocyanate, allophonates and polymeric oligomers. Modified
polyisocyanates can also be used, including but not limited to
carbodiimides and uretdiones, and mixtures thereof. Suitable
materials include, without limitation, those available under the
designation DESMODUR from Bayer Corporation of Pittsburgh, Pa. and
include DESMODUR N 3200, DESMODUR N 3300, DESMODUR N 3400, DESMODUR
XP 2410, and DESMODUR XP 2580.
[0017] As used herein, "isocyanate prepolymer" includes
polyisocyanate that is pre-reacted with a polyamine,
sulfur-containing compound having a reactive group and/or another
isocyanate reactive group such as polyol. Suitable polyisocyanates
include those previously disclosed herein. Suitable polyamines are
numerous and may be selected from a wide variety known in the art.
Examples of suitable polyamines include but are not limited to
primary and secondary amines, and mixtures thereof, such as any of
those listed herein. Amine terminated polyureas may also be used.
Amines comprising tertiary amine functionality can be used provided
that the amine further comprises at least two primary and/or
secondary amino groups. Suitable polyols are numerous and may be
selected from a wide variety known in the art. Examples of suitable
polyols include but are not limited to polyether polyols, polyester
polyols, polyurea polyols (e.g. the Michael reaction product of an
amino function polyurea with a hydroxyl functional (meth)acrylate),
polycaprolactone polyols, polycarbonate polyols, polyurethane
polyols, poly vinyl alcohols, addition polymers of unsaturated
monomers with pendant hydroxyl groups such as those containing
hydroxy functional (meth)acrylates, allyl alcohols and mixtures
thereof.
[0018] In certain embodiments, the isocyanate includes an
isocyanate prepolymer and in other embodiments the isocyanate
includes an isocyanate prepolymer and one or more additional
isocyanates, such as one or more of the polyisocyanates described
above.
[0019] As noted above, the polyurea/polythiourea of the present
compositions is formed from a reaction mixture comprising an
isocyanate component and an amine component.
[0020] Suitable amines for use in the amine component of the
present invention can be selected from a wide variety of known
amines, such as primary and secondary amines, and mixtures thereof
including polyamines having at least two functional groups, such as
di-, tri-, or higher functional polyamines and mixtures thereof.
The amine or amines used may be aromatic or aliphatic, such as
cycloaliphatic, or mixtures thereof. Suitable monoamines include
but are not limited to primary amines of the formula
R.sub.8--NH.sub.2, where R.sub.8 is a hydrocarbon radical that may
represent a straight chain or branched alkyl group, an aryl-alkyl
group, a hydroxyalkyl group or an alkoxyalkyl group. Other examples
of suitable aliphatic mono and polyamines include but are not
limited to ethylamine, isomeric propylamines, butylamines (e.g.
butylamine, isobutylamine, sec-butylamine, and tert-butylamine),
pentylamines, hexylamines, cyclohexylamine, ethylene diamine,
1,2-diaminopropane, 1,4-diaminobutane, 1,3-diaminopentane (DYTEK
EP, Invista), 1,6-diaminohexane, 2-methyl-1,5-pentane diamine
(DYTEK A, Invista), 2,5-diamino-2,5-dimethylhexane, 2,2,4- and/or
2,4,4-trimethyl-1,6-diamino-hexane, 1,11-diaminoundecane,
1,12-diaminododecane, 1,3- and/or 1,4-cyclohexane diamine,
1-amino-3,3,5-trimethyl-5-aminomethyl-cyclohexane, 2,4- and/or
2,6-hexahydrotoluoylene diamine, 2,4'-diaminodicyclohexyl methane,
4,4'-diaminodicyclohexyl methane (PACM-20, Air Products) and
3,3'-dialkyl-4,4'-diaminodicyclohexyl methanes (such as
3,3'-dimethyl-4,4'-diaminodicyclohexyl methane (DIMETHYL DICYKAN or
LAROMIN C260, BASF; ANCAMINE 2049, Air Products) and
3,3'-diethyl-4,4'-diaminodicyclohexyl methane), 2,4- and/or
2,6-diaminotoluene and 2,4'- and/or 4,4'-diaminodiphenyl methane,
or mixtures thereof. Additional suitable amines include but are not
limited to 2-ethylhexylamine, octylamine, tert-octylamine,
dodecylamine, octadecylamine, 3-(cyclohexylamine)propylamine,
3,3'-[1,4-butanediylbis]-1-propanamine, and diamino functional
polyetheramines having aliphatically bound primary amino groups,
examples of which include JEFFAMINE D-230, JEFFAMINE D-400,
JEFFAMINE D-2000, and JEFFAMINE D-4000 available from Huntsman
Corporation. It will be appreciated that when the amine is
hindered, the reaction time between the amine and the isocyanate
may be slower. This gives a longer pot-life or work-processing time
in those situations where a longer processing time is desired.
[0021] In certain embodiments the polyamine is a triamine. Examples
of suitable triamines include dipropylene triamine,
bis(hexamethylene)triamine and triamino functional
polyetherpolyamines having aliphatically bound primary amino groups
(JEFFAMINE T-403, JEFFAMINE T-3000, JEFFAMINE T-5000 from Huntsman
Corporation.) In other embodiments the amine can be a tetraamine or
other higher functional amine.
[0022] The amine component may comprise an amine/(meth)acrylate
oligomeric reaction product, and/or one or more other amine
curatives. As used herein, and as will be appreciated by those
skilled in the art, "(meth)acrylate" and like terms refers to both
the acrylate and the corresponding methacrylate. For example, the
second component may comprise one or more amines that are the
reaction product of a polyamine, a poly(meth)acrylate, and a
mono(meth)acrylate or a monoamine, such as those described in U.S.
patent application Ser. No. 11/611,979, incorporated by reference
herein; one or more amines that are the reaction product of an
amine, a (meth)acrylate and a dialkyl maleate and/or dialkyl
fumarate, such as those described in U.S. patent application Ser.
No. 11/611,988, incorporated by reference herein; one or more
amines that are the reaction product of a polyamine and a
mono(meth)acrylate, such as those described in U.S. patent
application Ser. No. 11/611,982, incorporated by reference herein;
one or more amines that are the reaction product of a monoamine and
a (meth)acrylate, such as those described in U.S. patent
application Ser. No. 11/611,984, incorporated by reference herein;
and/or one or more amines that are the reaction product of a
triamine and a dialkyl maleate and/or dialkyl fumarate, such as
those described in U.S. patent application Ser. No. 11/611,986,
incorporated by reference herein.
[0023] The present compositions, as noted above, can additionally
include other amines, such as those known in the art including but
not limited to any polyamines or combinations thereof listed
herein. Other amines include secondary cycloaliphatic diamines such
as JEFFLINK 754 (Huntsman Corporation, Houston, Tex.) and CLEARLINK
1000 (Dorf-Ketal Chemicals, LLC), aspartic ester functional amines,
such as those available under the name DESMOPHEN such as DESMOPHEN
NH1220, DESMOPHEN NH 1420, and DESMOPHEN NH 1520 (Bayer
Corporation), other aspartic ester functional materials, such as
the reaction products of triamines that comprise at least one
secondary amino group prior to reaction with a dialkyl maleate
and/or dialkyl fumarate including but not limited to the reaction
products of diethylene triamine, dipropylene triamine, and
bis-hexamethylene triamine with a dialkyl maleate and/or dialkyl
fumarate; examples of such materials include the adduct of
dipropylene triamine and diethyl maleate, the adduct of dipropylene
triamine and dibutyl maleate, the adduct of bis-hexamethylene
triamine with diethyl maleate, and the adduct of bis-hexamethylene
triamine with dibutyl maleate. Polyoxyalkyleneamines are also
suitable. Polyoxyalkyleneamines comprise two of more primary or
secondary amino groups attached to a backbone, derived, for
example, from propylene oxide, ethylene oxide, butylene oxide or a
mixture thereof. Examples of such amines include those available
under the designation JEFFAMINE, such as, without limitation,
JEFFAMINE D-230, D-400, D-2000, HK-511, ED-600, ED-900, ED-2003,
T-403, T-3000, T-5000, SD-231, SD-401, SD-2001, and ST-404
(Huntsman Corporation). Such amines have an approximate molecular
weight ranging from 200 to 7500.
[0024] Other suitable secondary amines that can be included in the
present composition are reaction products of materials comprising
primary amine functionality with acrylonitrile. Suitable amines
include any polyamine listed herein comprising primary amino
functionality. One example of such a material is the adduct of
4,4'-diaminodicyclohexylmethane and acrylonitrile. An example of a
commercially available material is the adduct of isophorone diamine
and acrylonitrile sold under the designation POLYCLEAR 136, (Hansen
Group LLC).
[0025] Other amines that can be used are adducts of primary
polyamines with mono or polyepoxies; an example of such a material
is the adduct of isophorone diamine with CARDURA E10P (available
from Hexion Speciality Chemicals, Inc).
[0026] In certain embodiments, the second component of the
composition, and/or the composition itself, are substantially free
of primary amine functionality (unreacted primary amino groups).
"Substantially free of primary amine functionality" and like terms
means that theoretically there is no primary amine functionality
but there maybe some primary amine functionality present that is
purely incidental, i.e. impurities in amines that are otherwise
secondary amine functional and/or trace primary amine functionality
that did not react.
[0027] As noted above, the first and/or second component of the
present compositions further comprises a sulfur-containing
compound. As used herein, the term "sulfur-containing compound"
refers to any compound having at least one sulfur atom, including,
but not limited to, a thiol, a polythiol, a thioether, a
polythioether and a polysulfide. A "thiol" as used herein refers to
a compound having a thiol or mercaptan group, that is, an "SH"
group. A "polythiol" refers to such a compound having more than one
SH group, such as a dithiol or higher functionality thiol. Such
groups are typically terminal and/or pendent such that they have an
active hydrogen that is reactive with other functional groups. A
"thioether" or "polythioether" refers to a compound that contains
one or more sulfur atoms, respectively, such as within the backbone
of the polymer, that do not contain an active hydrogen group; that
is, they are bonded on either side to another sulfur atom, a carbon
atom, and the like. A "polythiol" can comprise both a terminal
and/or pendant sulfur (--SH) and a non-reactive sulfur atom
(--S--). Thus, the term "polythiol" generally encompassed
"polythioether" as well. Suitable polythiols include, for example,
those disclosed in U.S. Pat. No. 7,009,032, incorporated by
reference herein. Any sulfur-containing compound used according to
the present invention can further comprise additional
functionality, including but not limited to hydroxyl functionality
and epoxy functionality.
[0028] In certain embodiments, the sulfur-containing compound can
comprise, but is not limited to, an amine/hydroxy-functional
polythioether. As used herein, the term "amine/hydroxy-functional
polythioether" refers to polythioethers containing one or more
amine functional groups and/or one or more hydroxy functional
groups. In certain embodiments of the present invention, the
amine/hydroxy-functional polythioether comprises at least one, in
some cases two, primary amine groups, at least one, in some cases
two, secondary amine groups, and at least one, in some cases two,
hydroxy groups.
[0029] The amine/hydroxy functional polythioethers utilized in
certain embodiments of the present invention can be made by any of
a variety of methods. In certain embodiments, the amine/hydroxy
functional polythioether is derived from an epoxy functional
polythioether. As used herein, the term "epoxy functional
polythioether" refers to a compound comprising a polythioether and
one or more epoxy functional groups. In certain embodiments, the
amine/hydroxy functional polythioether is derived from an
epoxy-functional polythioether including the structure (I):
##STR00001##
wherein R.sup.21 denotes a C.sub.2-10 n-alkylene group, such as a
C.sub.2-6 n-alkylene group; a C.sub.2-6 branched alkylene group,
such as a C.sub.3-6 branched alkylene group having one or more
pendant groups which can be, for example, alkyl groups, such as
methyl or ethyl groups; an alkyleneoxy group; a C.sub.6-8
cycloalkylene group; a C.sub.6-10 alkylcycloalkylene group; a
heterocyclic group; or
--[(--CHR.sup.3--).sub.s--X--].sub.q(--CHR.sup.3--).sub.r--,
wherein s is an integer having a value ranging from 2 to 6, q is an
integer having a value ranging from 1 to 5, r is an integer having
a value ranging from 2 to 10, R.sup.3 is hydrogen or methyl, and X
denotes O, S, or --NR.sub.2--, wherein R denotes an alkyl group;
and each R.sup.22 is a divalent linking group, such as alkylene or
oxyalkylene containing from 3 to 20 carbon atoms.
[0030] In certain embodiments, R.sup.21 in structure (I) is derived
from a compound, monomer, and/or polymer having at least two thiol
groups, such as, for example, a compound having the structure
(II):
HS--R.sup.1--SH (II)
wherein R.sup.1 is as defined above for R.sup.21 in structure
(I).
[0031] Suitable dithiols for use in preparing the epoxy functional
polythiother used to produce the amine/hydroxy functional
polythioethers utilized in certain embodiments of the present
invention include the compounds of structure (II) which are dithiol
compounds. In certain embodiments, such dithiols include those
compounds in which R.sup.1 is a C.sub.2-6 n-alkylene group, i.e.,
1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithiol,
1,5-pentanedithiol or 1,6-hexanedithiol.
[0032] Other suitable dithiols include those compounds in which
R.sup.1 is a C.sub.3-6 branched alkylene group, having one or more
pendent groups which can be, for example, methyl or ethyl groups.
Suitable compounds having branched alkylene R.sup.1 include
1,2-propanedithiol, 1,3-butanedithiol, 2,3-butanedithiol,
1,3-pentanedithiol and 1,3-dithio-3-methylbutane. Other useful
dithiols include those in which R.sup.1 is a C.sub.6-8
cycloalkylene or C.sub.6-10 alkylcycloalkylene group, for example,
dipentenedimercaptan and ethylcyclohexyldithiol (ECHDT).
[0033] Further suitable dithiols include one or more heteroatom
substituents in the carbon backbone, that is, dithiols in which X
is a heteroatom such as O, S or another bivalent heteroatom
radical; a secondary or tertiary amine group, i.e., --NR.sup.6--,
where R.sup.6 is hydrogen or methyl; or another substituted
trivalent heteroatom. In certain embodiments, X is O or S, and thus
R.sup.1 is
--[(--CHR.sup.3--).sub.s--O--].sub.q--(--CHR.sup.3--).sub.r-- or
--[(--CHR.sup.3--).sub.s--S--].sub.q--(--CHR.sup.3--).sub.r--. In
certain embodiments, the indices s and r are equal, and, in some
cases, both have the value of 2. Exemplary dithiols of this type
include dimercaptodiethylsulfide (DMDS) (s, r=2, q=1, X=S);
dimercaptodioxaoctane (DMDO) (s, q, r=2, X=0); and
1,5-dimercapto-3-oxapentane (s, r=2, q=1, X=0). It is also possible
to employ dithiols that include both heteroatom substituents in the
carbon backbone and pendent alkyl, such as methyl, groups. Such
compounds include methyl-substituted DMDS, such as
HS--CH.sub.2CH(CH.sub.3)--S--CH.sub.2CH.sub.2--SH,
HS--CH(CH.sub.3)CH.sub.2--S--CH.sub.2CH.sub.2--SH and dimethyl
substituted DMDS, such as
HS--CH.sub.2CH(CH.sub.3)--S--CH(CH.sub.3)CH.sub.2--SH and
HS--CH(CH.sub.3)CH.sub.2--S--CH.sub.2CH(CH.sub.3)--SH. Two or more
different dithiols of structure (II) can also be employed if
desired.
[0034] In certain embodiments of epoxy-functional polythioethers
having the structure (I), R.sup.21 may be a C.sub.2-6 n-alkylene
group, for example, 1,2-ethylenedithiol, 1,3-propylenedithiol,
1,4-butylenedithiol, 1,5-pentylenedithiol, or 1,6-hexylenedithiol.
In other embodiments, R.sup.21 in structure (I) may be a C.sub.3-6
branched alkylene group having one or more pendent groups, for
example, 1,2-propylenedithiol, 1,3-butylenedithiol,
2,3-butylenedithiol, 1,3-pentylenedithiol, and
1,3-dithio-3-methylbutylene. In certain embodiments, R.sup.21 may
be a C.sub.6-8 cycloalkylene or C.sub.6-10 alkylcycloalkylene
group, for example, dipentylenedimercaptan, and
ethylcyclohexylenedithiol (ECHDT).
[0035] In certain embodiments, the amine/hydroxy functional
polythioether included in the compositions of the present invention
is derived from an epoxy functional polythioether that is, in turn,
prepared by reacting, for example, a divinyl ether or mixture of
divinyl ethers with an excess of a dithiol or a mixture of
dithiols. In certain embodiments, (n+1) moles of a polythiol having
the structure (II) or a mixture of at least two polythiols having
the structure (II) are reacted with (n) moles of a polyvinyl ether
having the structure (III):
CH.sub.2.dbd.CH--O--(--R.sup.2--O--).sub.m--CH.dbd.CH.sub.2
(III)
or a mixture of at least two different compounds having the
structure (III), in the presence of a catalyst. In structure (III),
R.sup.2 denotesmethylene; a C.sub.2-10 n-alkylene group, such as a
C.sub.2-6 n-alkylene group; a C.sub.2-6 branched alkylene group,
such as a C.sub.3-6 branched alkylene group; a C.sub.6-8
cycloalkylene group; a C.sub.6-14 alkylcycloalkylene, such as a
C.sub.6-10 alkylcycloalkylene; a heterocyclic group, or
--[(--CHR.sup.3--).sub.s--X--].sub.q--(--CHR.sup.3--).sub.r--,
wherein s, q, r, R.sup.3 and X are as defined above in structure
(I); and m is a rational number having a value ranging from 0 to
50, such as 0 to 10 or 1 to 10. This method affords a
thiol-terminated difunctional polythioether.
[0036] The compounds of structure (III) are divinyl ethers. Divinyl
ether itself (m=0) can be used. Other suitable divinyl ethers
include those compounds having at least one oxyalkylene group, such
as from 1 to 4 oxyalkylene groups (i.e., those compounds in which m
is an integer from 1 to 4). In certain embodiments, m is an integer
from 2 to 4. It is also possible to employ commercially available
divinyl ether mixtures in producing suitable polythioethers. Such
mixtures are characterized by a non-integral average value for the
number of alkoxy units per molecule. Thus, m in structure (III) can
also take on non-integral, rational values between 0 and 10, such
as between 1 and 10, or, in some cases, between 1 and 4, such as
between 2 and 4.
[0037] Exemplary divinyl ethers include those compounds in which
R.sup.2 is C.sub.2-6 n-alkylene or C.sub.2-6 branched alkylene,
such as ethylene glycol divinyl ether (EG-DVE) (R.sup.2=ethylene,
m=1); butanediol divinyl ether (BD-DVE) (R.sup.2 butylene, m=1);
hexanediol divinyl ether (HD-DVE) (R.sup.2=hexylene, m=1);
diethylene glycol divinyl ether (DEG-DVE) (R.sup.2=ethylene, m=2);
triethylene glycol divinyl ether (R.sup.2=ethylene, m=3);
tetraethylene glycol divinyl ether (R.sup.2=ethylene, m=4) and
polytetrahydrofuryl divinyl ether. In certain embodiments, the
polyvinyl ether monomer can further comprise one or more pendent
groups selected from alkylene groups, hydroxyl groups, alkeneoxy
groups, and amine groups. Useful divinyl ether blends include
"PLURIOL.RTM." type blends such as PLURIOL.RTM. E-200 divinyl ether
(commercially available from BASF), for which R.sup.2=ethyl and
m=3.8, as well as "DPE" polymeric blends such as DPE-2 and DPE-3
(commercially available from International Specialty Products,
Wayne, N.J.).
[0038] Useful divinyl ethers in which R.sup.2 is C.sub.2-6 branched
alkylene can be prepared by reacting a polyhydroxy compound with
acetylene. Exemplary compounds of this type include compounds in
which R.sup.2 is an alkyl-substituted methylene group such as
--CH(CH.sub.3)-- or an alkyl-substituted ethylene such as
--CH.sub.2CH(CH.sub.3)--.
[0039] Other useful divinyl ethers include compounds in which
R.sup.2 is polytetrahydrofuryl (poly-THF) or polyoxyalkylene, in
some cases having an average of about 3 monomer units.
[0040] In some cases, trivinyl ether monomers such as
trimethylolpropane trivinyl ether; tetrafunctional vinyl ether
monomers such as pentaerythritol tetravinyl ether; and mixtures
thereof, can be used.
[0041] Two or more compounds of the structure (III) can be used.
Thus, in certain embodiments, two compounds of structure (II) and
one compound of structure (III), one compound of formula structure
(II) and two compounds of structure (III), two compounds of
structure (II) and of structure (III), and more than two compounds
of one or both structures, can be used to produce a variety of
polythioethers, and all such combinations of compounds are
contemplated as being suitable for use in the present
invention.
[0042] Although, as indicated above, compounds of the structures
(II) and (III) which have pendent alkyl groups, for example pendent
methyl groups, are useful in the invention, compounds of the
structures (II) and (III), which are free of pendent methyl or
other alkyl groups, also afford polythioethers that are suitable
for use in the present invention.
[0043] The reaction between the compounds of structures (II) and
(III) is sometimes catalyzed by a free radical catalyst. Suitable
free radical catalysts include azo compounds, for example
azobisnitrile compounds such as azo(bis)isobutyronitrile (AIBN);
organic peroxides such as benzoyl peroxide and t-butyl peroxide;
and similar free-radical generators. The reaction can also be
effected by irradiation with ultraviolet light either with or
without the use of a photosensitizer, such as benzophenone.
[0044] The reaction between a dithiol and a polyvinyl ether to
prepare a polythiol having the structure (II) is also described in
U.S. Pat. No. 5,912,319.
[0045] In structure (I), R.sup.22 is a divalent linking group. In
certain embodiments, R.sup.22 may be derived from a monoepoxide
having the structure (IV):
##STR00002##
in which R.sup.22 includes groups that are reactive with thiols
such as, for example, olefinic groups. The olefinic group may be an
alkylene group or an oxyalkylene group having from 3 to 20 carbon
atoms, such as from 3 to 5 carbon atoms. In certain embodiments,
the monoepoxides having the structure (IV) include allyl glycidyl
ether, 1,2-epoxy-5-hexene, 1,2-epoxy-7-octene, 1,2-epoxy-9-decene,
4-vinyl-1-cyclohexene 1,2-epoxide, butadiene monoepoxide, isoprene
monoepoxide, and limonene monoepoxide.
[0046] In certain embodiments, therefore, the amine/hydroxy
functional polythioether included in the compositions of the
present invention is derived from an epoxy functional polythioether
that is the reaction product of a dithiol, a diolefin, and a
monoepoxy olefin, having the following structure (V):
##STR00003##
in which R.sup.21 and R.sup.22 are as described above with respect
to structure (I); p is an integer from 2 to 6, m is a rational
number having a value ranging from 0 to 50, such as 0 to 10 or 1 to
10, n is an integer from 1 to 60, such as 1 to 10, in some cases 2;
and each R.sup.23 is a divalent linking group.
[0047] Suitable epoxy-functional polythioethers are commercially
available under the tradename Permapol.RTM. L-5534 from PRC-DeSoto
International, Inc., Burbank, Calif.
[0048] In certain embodiments, the amine/hydroxy functional
polythioethers utilized in certain embodiments of the present
invention are prepared by reacting one or more epoxy functional
polythioethers of the type previously described with an excess of
one or more polyamines. Thus, in certain embodiments, for example,
(n) moles of one or more epoxy functional polythioethers are
reacted with (>n) moles of one or more polyamines comprising two
or more amine groups per molecule.
[0049] Polyamines suitable for use in the production of the
amine/hydroxy functional polythioethers utilized in certain
embodiments of the present invention are numerous and can vary
widely. Such polyamines can include those that are known in the
art, and can include, but are not limited to, any of the polyamines
previously disclosed herein.
[0050] As will be appreciated from the foregoing description, in
certain embodiments, the compositions of the present invention
comprise an amine/hydroxy functional polythioether of the structure
(VI):
##STR00004##
in which R.sup.21, R.sup.22, R.sup.23, p, m and n are as were
defined above with respect to structure (V) and Y is an amine group
containing moiety, in some cases a primary amine group containing
moiety comprising one or more aromatic rings.
[0051] In certain embodiments, the amine/hydroxy functional
polythioether described above is a liquid at room temperature.
Moreover, in certain embodiments, the previously described
amine/hydroxy functional polythioether has a viscosity, at 100%
solids, of no more than 50 poise, such as no more than 10 poise, as
measured at a temperature of about 25.degree. C. and a pressure of
760 mm Hg determined according to ASTM D-2849 .sctn.79-90 using a
Brookfield CAP 2000 viscometer. Any end point within the foregoing
ranges can be used.
[0052] In certain embodiments, the amine/hydroxy functional
polythioether described above has a number average molecular weight
of 500 to 2000 grams per mole, such as 1200 to 1300 grams per mole,
the molecular weight being determined by gel-permeation
chromatography using a polystyrene standard. Any endpoints within
the foregoing ranges can be used.
[0053] The Examples herein further illustrate suitable methods for
making an amine/hydroxy functional polythioether suitable for use
in the present invention.
[0054] The sulfur-containing compound can also be the form of a
prepolymer. This is particularly relevant if the sulfur-containing
compound is in the isocyanate component. It will be appreciated
that inclusion of a sulfur-containing compound having an active
hydrogen in the isocyanate component will result in a reaction
between the active hydrogen and the isocyanate. Accordingly, when
used in the isocyanate component, the sulfur-containing compound
should have substantially no residual active hydrogens that will
react with the isocyanate. A prepolymer formed between the
sulfur-containing compound and the isocyanate can be made, such as
one prepared by reacting a mercaptan terminated disulfide with an
isocyanate.
[0055] In certain embodiments, the prepolymer can comprise, but is
not limited to, an isocyanate functional polythioether-polyurethane
and/or polythiourethane. As used herein, the term "isocyanate
functional polythioether-polyurethane and/or polythiourethane"
refers to a compound comprising a polythioether, at least one of a
urethane linkage (--NH--C(O)--O--) and/or a thiourethane linkage
(--NH--C(O)--S--), and one or more isocyanate functional groups. In
certain embodiments, the isocyanate functional
polythioether-polyurethane and/or polythiourethane utilized in the
present invention comprises a plurality of isocyanate groups, in
some case two isocyanate groups, per molecule.
[0056] The isocyanate functional polythioether-polyurethanes and/or
polythiourethanes included in certain embodiments of the
compositions of the present invention can be prepared, for example,
by reacting one or more isocyanate reactive polythioethers, such as
thiol-functional and/or hydroxy-functional polythioethers, with an
excess of one or more isocyanate functional compounds, as discussed
in detail below.
[0057] In certain embodiments, the isocyanate functional
polythioether-polyurethane and/or polythiourethane included in the
compositions of the present invention is derived from a
polythioether comprising at least two reactive thiol groups, in
some cases, such a polythioether has two reactive thiol groups.
Each thiol group, that is, the --SH group, is capable of forming a
thiourethane linkage, i.e., a --NH--C(O)--S-- linkage, with an
isocyanate group.
[0058] In certain embodiments, the polythioether comprising at
least two reactive thiol groups comprises a difunctional
thiol-terminated polythioether, such as, for example, those having
the following structure (VI):
HS--R.sup.1--[--S--(CH.sub.2).sub.p--O--[--R.sup.2--O--].sub.m--(CH.sub.-
2).sub.2--S--R.sup.1--].sub.n--SH, (VI)
wherein each R.sup.1 independently denotes a C.sub.2-10 n-alkylene
group, such as a C.sub.2-6 n-alkylene group; a C.sub.2-6 branched
alkylene group, such as a C.sub.3-6 branched alkylene group having
one or more pendant groups which can be, for example, alkyl groups,
such as methyl or ethyl groups; an alkyleneoxy group; a C.sub.6-8
cycloalkylene group; a C.sub.6-10 alkylcycloalkylene group; a
heterocyclic group; or
[(--CHR.sup.3--).sub.s--X--].sub.q--(--CHR.sup.3--).sub.r--,
wherein s is an integer having a value ranging from 2 to 6, q is an
integer having a value ranging from 1 to 5, r is an integer having
a value ranging from 2 to 10, R.sup.3 is hydrogen or methyl, and X
denotes O, S, or --NR.sub.2--, wherein R denotes an alkyl group;
R.sup.2 independently denotes methylene; a C.sub.2-10 n-alkylene
group, such as a C.sub.2-6 n-alkylene group; a C.sub.2-6 branched
alkylene group, such as a C.sub.3-6 branched alkylene group; a
C.sub.6-8 cycloalkylene group; a C.sub.6-14 alkylcycloalkylene,
such as a C.sub.6-10 alkylcycloalkylene; a heterocyclic group, or
--[(--CHR.sup.3--).sub.s--X--].sub.q--(--CHR.sup.3--).sub.r--;
wherein s, q, r, R.sup.3 and X are as defined above; m is a
rational number having a value ranging from 0 to 50, such as 0 to
10 or 1 to 10; n is an integer having a value ranging from 1 to 60;
and p is an integer having a value ranging from 2 to 6.
[0059] Such thiol-terminated polythioethers suitable for use in the
present invention can be prepared by a number of methods. In
certain embodiments, (n+1) moles of a compound of the earlier
described structure (II) or a mixture of at least two different
compounds having the structure (II), are reacted with (n) moles of
a compound of the earlier described structure (III) or a mixture of
at least two different compounds having the structure (III), in the
presence of a catalyst. This method affords a thiol-terminated
difunctional polythioether. Suitable dithiols and divinyl ethers
include, without limitation, those described in detail earlier.
[0060] In certain embodiments of the present invention, the
isocyanate functional polythioether-polyurethane and/or
polythiourethane included in the compositions of the present
invention is derived from a hydroxy-functional polythioether
comprising at least two reactive hydroxy groups, in some cases,
such a polythioether has two reactive hydroxy groups. As used
herein, the term "hydroxy group" refers to an --OH group that is
capable of forming a urethane linkage, i.e., a --NH--C(O)--O--
linkage, with an isocyanate group.
[0061] Hydroxy functional polythioethers suitable for use in the
present invention can be prepared by any suitable technique that
will be understood by those skilled in the art. In certain
embodiments of the present invention, the hydroxy functional
polythiother that is utilized is derived from a thiol-functional
polythioether of the type previously described herein. In these
embodiments, the thiol-functional polythioether can be converted to
a hydroxy-functional polythioether by reacting the thiol-functional
polythiother with, for example, a lower alkyl substituted epoxide.
For example, in the case of a difunctional thiol-terminated
polythioether, one mole of the polythioether can be reacted with
two moles of the lower alkyl substituted epoxide, such as propylene
oxide and/or ethylene oxide.
[0062] As previously indicated, the isocyanate functional
polythioether-polyurethanes and/or polythiourethanes included in
certain embodiments of the compositions of the present invention
can be prepared, for example, by reacting one or more
thiol-functional polythioethers and/or one or more
hydroxy-functional polythioethers, such as any of those described
above, with an excess of one or more isocyanate functional
compounds. Thus, in certain embodiments, for example, (n) moles of
one or more thiol-functional polythioethers and/or
hydroxy-functional polythioethers are reacted with (>n) moles of
one or more isocyanate functional compounds.
[0063] Suitable isocyanate functional compounds useful in preparing
the isocyanate functional polythioether-polyurethanes and/or
polythiourethanes utilized in certain embodiments of the present
invention are numerous and can vary widely. Such isocyanates can
include those that are known in the art, and can include, but are
not limited to, any of the isocyanates previously disclosed
herein.
[0064] As will be appreciated from the foregoing description, in
certain embodiments, the compositions of the present invention
comprise an isocyanate functional polythioether-polyurethane and/or
polythiourethane of the structure (VII):
##STR00005##
in which R.sup.1, R.sup.2, p, m, and n are as were defined above
with respect to structure (I), each X is independently O or S, and
each Y is independently an isocyanate group containing moiety, in
some cases an isocyanate group moiety comprising one or more
aromatic rings.
[0065] In certain embodiments, the isocyanate functional
polythioether-polyurethane and/or polythiourethane described above
is a liquid at room temperature. Moreover, in certain embodiments,
the previously described isocyanate functional
polythioether-polyurethane and/or polythiourethane has a viscosity,
at 100% solids, of no more than 400 poise, such as 30-200 poise, at
a temperature of about 25.degree. C. and a pressure of about 760 mm
Hg determined according to ASTM D-2849 .sctn.79-90 using a
Brookfield CAP 2000 viscometer. Any endpoint within the foregoing
ranges can also be used.
[0066] In certain embodiments, the isocyanate functional
polythioether-polyurethane and/or polythiourethane described above
has a number average molecular weight of 500 to 2000 grams per
mole, such as 800 to 950 grams per mole, the molecular weight being
determined by gel-permeation chromatography using a polystyrene
standard. Any endpoints within the foregoing ranges can also be
used.
[0067] The Examples herein further illustrate suitable methods for
making isocyanate functional polythioether-polyurethanes and/or
polythiourethanes that are suitable for use in the present
invention.
[0068] In certain embodiments, the isocyanate functional
polythioether-polyurethane and/or polythiourethane can be added to
the isocyanate component and/or the amine/hydroxy-functional
polythioether can be added to the amine component.
[0069] In certain embodiments, the polythiol comprises a
thioether-functional polythiol prepared by reacting together
compound (a) having at least two thiol functional groups, and
compound (b) having triple bond functionality. In certain
embodiments, the compound having triple bond functionality will be
a hydroxyl functional compound, and the thioether-functional
polythiol will have pendant hydroxyl functional groups.
[0070] The compound (a) having at least two thiol functional groups
may comprise, for example, a polythiol or mixture thereof. In
certain embodiments, the polythiol comprises dithiol, and in
certain embodiments the polythiol comprises a mixture of a dithiol
and another compound having more than two thiol functional groups
(higher polythiol). Such mixtures may include mixtures of dithiols
and/or mixtures of higher polythiols. The thiol functional groups
(--SH groups) are typically terminal groups, though a minor portion
(such as less than 50%, or less than 25%, of all thiol groups) may
be pendant along a chain. The compound (a) may additionally contain
a minor portion (such as less than 50%, or less than 25%, of all
functional groups) of other active hydrogen functionality (that is,
different from thiol), for example, hydroxyl functionality. The
compound (a) may be linear or branched, and may contain cyclic,
alkyl, aryl, aralkyl, or alkaryl groups.
[0071] The compound (a) can be selected so as to produce a
substantially linear oligomeric polythiol. Therefore, when compound
(a) comprises a mixture of a dithiol and a compound having more
than two thiol functional groups, the compound having more than two
thiol functional groups can be present in an amount that will
maintain the linear nature of the polymer, such as up to 10 percent
by weight of the mixture.
[0072] Suitable dithiols can include linear or branched aliphatic,
cycloaliphatic, aromatic, heterocyclic, polymeric, oligomeric
dithiols and mixtures thereof. The dithiol can comprise a variety
of linkages including but not limited to ether linkages (--O--),
sulfide linkages (--S--), polysulfide linkages (--S.sub.x--,
wherein x is at least 2, such as from 2 to 4) and combinations of
such linkages.
[0073] Non-limiting examples of suitable dithiols for use in the
present invention can include but are not limited to
2,5-dimercaptomethyl-1,4-dithiane, dimercaptodiethylsulfide (DMDS),
ethanedithiol, 3,6-dioxa-1,8-octanedithiol, ethylene glycol
di(2-mercaptoacetate), ethylene glycol di(3-mercaptopropionate),
poly(ethylene glycol) di(2-mercaptoacetate) and poly(ethylene
glycol) di(3-mercaptopropionate), benzenedithiol,
4-tert-butyl-1,2-benzenedithiol, 4,4'-thiodibenzenethiol, and
mixtures thereof.
[0074] The dithiol may include dithiol oligomers having disulfide
linkages such as materials represented by the following graphic
formula VIII:
##STR00006##
wherein n can represent an integer from 1 to 21.
[0075] Dithiol oligomers represented by Formula I can be prepared,
for example, by the reaction of 2,5-dimercaptomethyl-1,4-dithiane
with sulfur in the presence of basic catalyst, as known in the
art.
[0076] The nature of the SH group in polythiols is such that
oxidative coupling can occur readily, leading to formation of
disulfide linkages (that is, --S--S-- linkages). Various oxidizing
agents can lead to such oxidative coupling. The oxygen in the air
can in some cases lead to such oxidative coupling during storage of
the polythiol. It is believed that a possible mechanism for the
oxidative coupling of thiol groups involves the formation of thiyl
radicals, followed by coupling of said thiyl radicals, to form
disulfide linkage. It is further believed that formation of a
disulfide linkage can occur under conditions that can lead to the
formation of a thiyl radical, including but not limited to reaction
conditions involving free radical initiation. The polythiols for
use as compound (a) in the preparation of the polythiols of the
present invention can include species containing disulfide linkages
formed during storage.
[0077] The polythiols for use as compound (a) in the preparation of
the oligomeric polythiols used in certain embodiments of the
present invention also can include species containing disulfide
linkages formed during synthesis of the polythiol.
[0078] In certain embodiments, the dithiol for use in the present
invention can include at least one dithiol represented by the
following graphic formulas:
##STR00007##
[0079] The sulfide-containing dithiols comprising 1,3-dithiolane
(e.g., formulas IX and X) or 1,3-dithiane (e.g., formulas XI and
XII) can be prepared by reacting asym-dichloroacetone with
dimercaptan, and then reacting the reaction product with
dimercaptoalkylsulfide, dimercaptan or mixtures thereof, as
described in U.S. Pat. No. 7,009,032 B2.
[0080] Non-limiting examples of suitable dimercaptans for use in
the reaction with asym-dichloroacetone can include but are not
limited to materials represented by the following formula XIII:
##STR00008##
wherein Y can represent CH.sub.2 or (CH.sub.2--S--CH.sub.2), and n'
can be an integer from 0 to 5. The dimercaptan for reaction with
asym-dichloroacetone in the present invention can be chosen from,
for example, ethanedithiol, propanedithiol, and mixtures
thereof.
[0081] The amount of asym-dichloroacetone and dimercaptan suitable
for carrying out the above reaction can vary. For example,
asym-dichloroacetone and dimercaptan can be present in the reaction
mixture in an amount such that the molar ratio of dichloroacetone
to dimercaptan can be from 1:1 to 1:10.
[0082] Suitable temperatures for reacting asym-dichloroacetone with
dimercaptan can vary, often ranging from 0 to 100.degree. C.
[0083] Non-limiting examples of suitable dimercaptans for use in
the reaction with the reaction product of the asym-dichloroacetone
and dimercaptan can include but are not limited to materials
represented by the above general formula VI, aromatic dimercaptans,
cycloalkyl dimercaptans, heterocyclic dimercaptans, branched
dimercaptans, and mixtures thereof.
[0084] Non-limiting examples of suitable dimercaptoalkylsulfides
for use in the reaction with the reaction product of the
asym-dichloroacetone and dimercaptan include but are not limited to
materials represented by the following formula:
##STR00009##
wherein X can represent O, S or Se, n'' can be an integer from 0 to
10, m can be an integer from 0 to 10, p can be an integer from 1 to
10, q can be an integer from 0 to 3, and with the proviso that
(m+n'') is an integer from 1 to 20.
[0085] Non-limiting examples of suitable dimercaptoalkylsulfides
for use in the present invention can include branched
dimercaptoalkylsulfides.
[0086] The amount of dimercaptan, dimercaptoalkylsulfide, or
mixtures thereof, suitable for reacting with the reaction product
of asym-dichloroacetone and dimercaptan, can vary. Typically,
dimercaptan, dimercaptoalkylsulfide, or a mixture thereof, can be
present in the reaction mixture in an amount such that the
equivalent ratio of reaction product to dimercaptan,
dimercaptoalkylsulfide, or a mixture thereof, can be from 1:1.01 to
1:2. Moreover, suitable temperatures for carrying out this reaction
can vary within the range of from 0 to 100.degree. C.
[0087] The reaction of asym-dichloroacetone with dimercaptan can be
carried out in the presence of an acid catalyst. The acid catalyst
can be selected from a wide variety known in the art, such as but
not limited to Lewis acids and Bronsted acids. Non-limiting
examples of suitable acid catalysts can include those described in
Ullmann's Encyclopedia of Industrial Chemistry, 5.sup.th Edition,
1992, Volume A21, pp. 673 to 674. The acid catalyst is often chosen
from boron trifluoride etherate, hydrogen chloride, toluenesulfonic
acid, and mixtures thereof. The amount of acid catalyst can vary
from 0.01 to 10 percent by weight of the reaction mixture.
[0088] The reaction product of asym-dichloroacetone and dimercaptan
can alternatively be reacted with dimercaptoalkylsulfide,
dimercaptan or mixtures thereof, in the presence of a base. The
base can be selected from a wide variety known in the art, such as
but not limited to Lewis bases and Bronsted bases. Non-limiting
examples of suitable bases can include those described in Ullmann's
Encyclopedia of Industrial Chemistry, 5.sup.th Edition, 1992,
Volume A21, pp. 673 to 674. The base is often sodium hydroxide. The
amount of base can vary. Typically, a suitable equivalent ratio of
base to reaction product of the first reaction, can be from 1:1 to
10:1.
[0089] The reaction of asym-dichloroacetone with dimercaptan can be
carried out in the presence of a solvent. The solvent can be
selected from but is not limited to organic solvents. Non-limiting
examples of suitable solvents can include but are not limited to
chloroform, dichloromethane, 1,2-dichloroethane, diethyl ether,
benzene, toluene, acetic acid and mixtures thereof.
[0090] In another embodiment, the reaction product of
asym-dichloroacetone and dimercaptan can be reacted with
dimercaptoalkylsulfide, dimercaptan or mixtures thereof, in the
presence of a solvent, wherein the solvent can be selected from but
is not limited to organic solvents. Non-limiting examples of
suitable organic solvents can include alcohols such as but not
limited to methanol, ethanol and propanol; aromatic hydrocarbon
solvents such as but not limited to benzene, toluene, xylene;
ketones such as but not limited to methyl ethyl ketone; water; and
mixtures thereof.
[0091] The amount of solvent can widely vary, from 0 to 99 percent
by weight of the reaction mixtures. Alternatively, the reactions
can be carried out neat, i.e., without solvent.
[0092] The reaction of asym-dichloroacetone with dimercaptan can
also be carried out in the presence of a dehydrating reagent. The
dehydrating reagent can be selected from a wide variety known in
the art. Suitable dehydrating reagents for use in this reaction can
include but are not limited to magnesium sulfate. The amount of
dehydrating reagent can vary widely according to the stoichiometry
of the dehydrating reaction.
[0093] The compound (a) having at least two thiol functional groups
used to prepare the oligomeric polythiol used in certain
embodiments of the present invention can be prepared in certain
non-limiting embodiments by reacting
2-methyl-2-dichloromethyl-1,3-dithiolane with
dimercaptodiethylsulfide to produce dimercapto-1,3-dithiolane
derivative of formula III. Alternatively,
2-methyl-2-dichloromethyl-1,3-dithiolane can be reacted with
1,2-ethanedithiol to produce dimercapto-1,3-dithiolane derivative
of formula II. 2-methyl-2-dichloromethyl-1,3-dithiane can be
reacted with dimercaptodiethylsulfide to produce
dimercapto-1,3-dithiane derivative of formula V. Also,
2-methyl-2-dichloromethyl-1,3-dithiane can be reacted with
1,2-ethanedithiol to produce dimercapto-1,3-dithiane derivative of
formula IV.
[0094] Another non-limiting example of a dithiol suitable for use
as compound (a) in the preparation of the oligomeric polythiol used
in certain embodiments of the present invention can include at
least one dithiol oligomer prepared by reacting dichloro derivative
with dimercaptoalkylsulfide as follows in Reaction Scheme A:
##STR00010##
wherein R can represent CH.sub.3, CH.sub.3CO, C.sub.1 to C.sub.10
alkyl, cycloalkyl, aryl alkyl, or alkyl-CO; Y' can represent
C.sub.1 to C.sub.10 alkyl, cycloalkyl, C.sub.6 to C.sub.14 aryl,
(CH.sub.2).sub.p'(S).sub.m'(CH.sub.2).sub.q',
(CH.sub.2).sub.p'(Se).sub.m'(CH.sub.2).sub.q'(CH.sub.2).sub.p'(Te).sub.m'-
(CH.sub.2).sub.q', wherein m' can be an integer from 1 to 5 and, p'
and q' can each be an integer from 1 to 10; n''' can be an integer
from 1 to 20; and x can be an integer from 0 to 10.
[0095] The reaction of dichloro derivative with
dimercaptoalkylsulfide can be carried out in the presence of a
base. Suitable bases include any known to those skilled in the art
in addition to those disclosed above.
[0096] The reaction of dichloro derivative with
dimercaptoalkylsulfide may be carried out in the presence of a
phase transfer catalyst. Suitable phase transfer catalysts for use
in the present invention are known and varied. Non-limiting
examples can include but are not limited to tetraalkylammonium
salts and tetraalkylphosphonium salts. This reaction is often
carried out in the presence of tetrabutylphosphonium bromide as
phase transfer catalyst. The amount of phase transfer catalyst can
vary widely, from 0 to 50 equivalent percent, or from 0 to 10
equivalent percent, or from 0 to 5 equivalent percent, relative to
the dimercaptosulfide reactants.
[0097] The compound (a) having at least two thiol functional groups
may further contain hydroxyl functionality. Non-limiting examples
of suitable polythiol materials having hydroxyl groups can include
but are not limited to glycerin bis(2-mercaptoacetate), glycerin
bis(3-mercaptopropionate), 1,3-dimercapto-2-propanol,
2,3-dimercapto-1-propanol, trimethylolpropane
bis(2-mercaptoacetate), trimethylolpropane
bis(3-mercaptopropionate), pentaerythritol bis(2-mercaptoacetate),
pentaerythritol tris(2-mercaptoacetate), pentaerythritol
bis(3-mercaptopropionate), pentaerythritol
tris(3-mercaptopropionate), and mixtures thereof.
[0098] In addition to dithiols disclosed above, particular examples
of suitable dithiols for use as or in preparing the compound (a)
can include 1,2-ethanedithiol, 1,2-propanedithiol,
1,3-propanedithiol, 1,3-butanedithiol, 1,4-butanedithiol,
2,3-butanedithiol, 1,3-pentanedithiol, 1,5-pentanedithiol,
1,6-hexanedithiol, 1,3-dimercapto-3-methylbutane,
dipentenedimercaptan, ethylcyclohexyldithiol (ECHDT),
dimercaptodiethylsulfide (DMDS), methyl-substituted
dimercaptodiethylsulfide, dimethyl-substituted
dimercaptodiethylsulfide, 3,6-dioxa-1,8-octanedithiol,
1,5-dimercapto-3-oxapentane, 2,5-dimercaptomethyl-1,4-dithiane
(DMMD), ethylene glycol di(2-mercaptoacetate), ethylene glycol
di(3-mercaptopropionate), and mixtures thereof.
[0099] Suitable trifunctional or higher-functional polythiols for
use in compound (a) can be selected from a wide variety known in
the art. Non-limiting examples can include pentaerythritol
tetrakis(2-mercaptoacetate), pentaerythritol
tetrakis(3-mercaptopropionate), trimethylolpropane
tris(2-mercaptoacetate), trimethylolpropane
tris(3-mercaptopropionate), and/or thioglycerol
bis(2-mercaptoacetate).
[0100] For example, the polythiol can be chosen from materials
represented by the following formula XV,
##STR00011##
wherein R.sub.1 and R.sub.2 can each be independently chosen from
straight or branched chain alkylene, cyclic alkylene, phenylene and
C.sub.1-C.sub.9 alkyl substituted phenylene. Non-limiting examples
of straight or branched chain alkylene can include but are not
limited to methylene, ethylene, 1,3-propylene, 1,2-propylene,
1,4-butylene, 1,2-butylene, pentylene, hexylene, heptylene,
octylene, nonylene, decylene, undecylene, octadecylene and
icosylene. Non-limiting examples of cyclic alkylenes can include
but are not limited to cyclopentylene, cyclohexylene,
cycloheptylene, cyclooctylene, and alkyl-substituted derivatives
thereof. The divalent linking groups R.sub.1 and R.sub.2 can be
chosen from methylene, ethylene, phenylene, and alkyl-substituted
phenylene, such as methyl, ethyl, propyl, isopropyl and nonyl
substituted phenylene.
[0101] In particular embodiments, the compound (a) having at least
two thiol functional groups may be prepared by reacting together
(1) any of the dithiols mentioned above, and (2) a compound having
at least two double bonds (for example, a diene). Such compounds
having at least two double bonds are described in more detail
below, as are reaction methods.
[0102] The compound (b) having triple bond functionality used to
prepare the oligomeric polythiol used in the present invention may
comprise any alkyne known to those skilled in the art. In certain
embodiments, the alkyne comprises a hydroxyl functional alkyne,
such as any of those known in the art. Because a triple bond can
react twice with a thiol functional group, for the purposes of the
present invention, a triple bond is understood to be equal to two
equivalents of a double bond when determining reaction
stoichiometry.
[0103] Suitable non-limiting examples of hydroxyl functional
compounds having triple bond functionality include propargyl
alcohol, 2-butyne-1,4-diol, 3-butyne-2-ol, 3-hexyne-2,5-diol,
and/or mixtures thereof. A portion of the hydroxyl functional
groups on the compound (b) may be esterified. For example, a
portion of the compound (b) may comprise an alkyne-functional ester
of a C.sub.1-C.sub.12 carboxylic acid such as propargyl acetate,
propargyl propionate, propargyl benzoate, and the like.
[0104] In the preparation of the oligomeric polythiol used in
certain embodiments of the present invention, the ratio of thiol
functional groups in compound (a) to triple bonds in compound (b)
typically ranges from 1.01:1 to 2.0:1, such as 1.5:1 to 2.0:1.
[0105] To prepare the oligomeric polythiols used in certain
embodiments of the present invention, the reaction of the compound
(a) with triple bond-containing compounds (b) can be carried out in
the presence of radical initiator. Suitable radical initiators for
use in the present invention can vary widely and can include those
known to one of ordinary skill in the art. Non-limiting examples of
radical initiators can include but are not limited to azo or
peroxide type free-radical initiators such as
azobisalkalenenitriles. The free-radical initiator can be
azobisalkalenenitrile, which is commercially available from DuPont
in their VAZO line. VAZO, VAZO-52, VAZO-64, VAZO-67, VAZO-88 and
mixtures thereof can also be used as radical initiators, for
example.
[0106] Selection of the free-radical initiator can depend on
reaction temperature. The reaction temperature can vary, for
example, from room temperature to 100.degree. C. VAZO 52 can be
used at a temperature of from 50-60.degree. C. VAZO 64 and VAZO 67
can be used at a temperature of 60-70.degree. C., and VAZO 88 can
be used at a temperature of 70-100.degree. C.
[0107] The amount of free radical initiator used in the reaction of
the present invention can vary widely and can depend on the free
radical initiator selected. Typically, the free radical initiator
is present in an amount of from 0.01% by weight to 5% by weight of
the reaction mixture.
[0108] The reaction of the compound (a) with the triple
bond-containing compound (b) can be carried out under a variety of
reaction conditions. Such conditions can depend on the degree of
reactivity of the triple bond containing compound and the desired
structure of the resulting polythiol oligomer. In one reaction
scheme, the reactants and a radical initiator can be combined
together while heating the mixture. Alternatively, the triple bond
containing-compound can be added in relatively small amounts over a
period of time to a mixture of polythiol and radical initiator at a
certain temperature. Also, the triple bond containing-compound can
be combined with the compound (a) having at least two thiol
functional groups in a stepwise manner under radical
initiation.
[0109] Certain embodiments of the present invention are further
directed to use of a thioether-functional polythiol prepared by
reacting together:
[0110] (a) a compound having at least two thiol functional groups
as described above;
[0111] (b) a compound having triple bond functionality as described
above; and
[0112] (c) a compound having at least two double bonds.
In certain embodiments, the compound having triple bond
functionality will be a hydroxyl functional compound, so the
polythiol will have pendant hydroxyl functional groups.
[0113] The compound (a) having at least two thiol functional groups
may be any thioether-functional, oligomeric polythiol, including
those described above. In certain embodiments, the compound (a)
comprises a reaction product of (1) any of the dithiols mentioned
above, and (2) a compound having at least two double bonds, which
may be the same as or different from the compound (c). The compound
(b) having triple bond functionality can be any such compound,
including those described above.
[0114] The compound (c) having at least two double bonds can be
chosen from non-cyclic dienes, including but not limited to
straight chain and/or branched aliphatic non-cyclic dienes,
non-aromatic ring-containing dienes, including non-aromatic
ring-containing dienes wherein the double bonds can be contained
within the ring or not contained within the ring or any combination
thereof, and wherein the non-aromatic ring-containing dienes can
contain non-aromatic monocyclic groups or non-aromatic polycyclic
groups or combinations thereof; aromatic ring-containing dienes; or
heterocyclic ring-containing dienes; or dienes containing any
combination of such non-cyclic and/or cyclic groups. The dienes can
optionally contain thioether, disulfide, polysulfide, sulfone,
ester, thioester, carbonate, thiocarbonate, urethane, or
thiourethane linkages, or halogen substituents, or combinations
thereof; with the proviso that the dienes contain at least some
double bonds capable of undergoing reaction with SH groups of a
polythiol, and forming covalent C--S bonds. In certain embodiments
the compound (c) having at least two double bonds comprises a
mixture of dienes that are different from one another.
[0115] The compound (c) having at least two double bonds may
comprise acyclic non-conjugated dienes, acyclic polyvinyl ethers,
allyl-(meth)acrylates vinyl-(meth)acrylates, di(meth)acrylate
esters of diols, di(meth)acrylate esters of dithiols,
di(meth)acrylate esters of poly(alkyleneglycol)diols, monocyclic
non-aromatic dienes, polycyclic non-aromatic dienes, aromatic
ring-containing dienes, diallyl esters of aromatic ring
dicarboxylic acids, divinyl esters of aromatic ring dicarboxylic
acids, and/or mixtures thereof.
[0116] Non-limiting examples of acyclic non-conjugated dienes can
include those represented by the following formula XVI:
##STR00012##
wherein R.sub.3 can represent C.sub.1 to C.sub.30 linear or
branched divalent saturated alkylene radical, or C.sub.2 to
C.sub.30 divalent organic radical including groups such as but not
limited to those containing ether, thioether, ester, thioester,
ketone, polysulfide, sulfone and combinations thereof. The acyclic
non-conjugated dienes can be selected from 1,5-hexadiene,
1,6-heptadiene, 1,7-octadiene and mixtures thereof.
[0117] Non-limiting examples of suitable acyclic polyvinyl ethers
can include those represented by the following formula XVII:
CH.sub.2.dbd.CH--O--(--R.sub.4--O--).sub.m''--CH.dbd.CH.sub.2
(XVII)
wherein R.sub.4 can be C.sub.2 to C.sub.6 n-alkylene, C.sub.3 to
C.sub.6 branched alkylene group, or
--[(CH.sub.2--).sub.p''--O--].sub.q''--(--CH.sub.2--).sub.r'--, m''
can be a rational number from 0 to 10, often 2; p'' can be an
integer from 2 to 6, q'' can be an integer from 1 to 5 and r' can
be an integer from 2 to 10.
[0118] Non-limiting examples of polyvinyl ether monomers suitable
for use can include but are not limited to divinyl ether monomers,
such as ethylene glycol divinyl ether, diethylene glycol divinyl
ether, triethyleneglycol divinyl ether, and mixtures thereof.
[0119] Di(meth)acrylate esters of linear diols can include but are
not limited to ethanediol di(meth)acrylate, 1,3-propanediol
dimethacrylate, 1,2-propanediol di(meth)acrylate, 1,4-butanediol
di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,2-butanediol
di(meth)acrylate, and mixtures thereof.
[0120] Di(meth)acrylate esters of dithiols can include but are not
limited to di(meth)acrylate of 1,2-ethanedithiol including
oligomers thereof, di(meth)acrylate of dimercaptodiethyl sulfide
(2,2'-thioethanedithiol di(meth)acrylate) including oligomers
thereof, di(meth)acrylate of 3,6-dioxa-1,8-octanedithiol including
oligomers thereof, di(meth)acrylate of 2-mercaptoethyl ether
including oligomers thereof, di(meth)acrylate of
4,4'-thiodibenzenethiol, and mixtures thereof.
[0121] Further non-limiting examples of suitable dienes can include
but are not limited to monocyclic aliphatic dienes such as those
represented by following graphic formula XVIII:
##STR00013##
wherein X' and Y'' each independently can represent C.sub.1-10
divalent saturated alkylene radical; or C.sub.1-5 divalent
saturated alkylene radical, containing at least one element
selected from the group of sulfur, oxygen and silicon in addition
to the carbon and hydrogen atoms; and R.sub.5 can represent H, or
C.sub.1-C.sub.10 alkyl; and those represented by the following
graphic formula XIX:
##STR00014##
wherein X' and R.sub.5 can be as defined above and R.sub.6 can
represent C.sub.2-C.sub.10 alkenyl. The monocyclic aliphatic dienes
can include 1,4-cyclohexadiene, 4-vinyl-1-cyclohexene, dipentene
and terpinene.
[0122] Non-limiting examples of polycyclic aliphatic dienes can
include 5-vinyl-2-norbornene; 2,5-norbornadiene; dicyclopentadiene
and mixtures thereof.
[0123] Non-limiting examples of aromatic ring-containing dienes can
include but are not limited to those represented by the following
graphic formula XX:
##STR00015##
wherein R.sub.7 can represent hydrogen or methyl. Aromatic
ring-containing dienes can include monomers such as diisopropenyl
benzene, divinyl benzene and mixtures thereof.
[0124] Examples of diallyl esters of aromatic ring dicarboxylic
acids can include but are not limited to those represented by the
following graphic formula XXI:
##STR00016##
wherein each m''' independently can be an integer from 0 to 5. The
diallyl esters of aromatic ring dicarboxylic acids can include
o-diallyl phthalate, m-diallyl phthalate, p-diallyl phthalate and
mixtures thereof.
[0125] In certain embodiments, the compound (c) having at least two
double bonds comprises 5-vinyl-2-norbornene, ethylene glycol
divinyl ether, diethylene glycol divinyl ether, triethylene glycol
divinyl ether, butane diol divinyl ether, vinylcyclohexene,
4-vinyl-1-cyclohexene, dipentene, terpinene, dicyclopentadiene,
cyclododecadiene, cyclooctadiene, 2-cyclopenten-1-yl-ether,
2,5-norbornadiene, divinylbenzene including but not limited to
1,3-divinylbenzene, 1,2-divinylbenzene, and/or 1,4-divinylbenzene,
diisopropenylbenzene including but not limited to
1,3-diisopropenylbenzene, 1,2-diisopropenylbenzene, and/or
1,4-diisopropenylbenzene, allyl(meth)acrylate, ethanediol
di(meth)acrylate, 1,3-propanediol di(meth)acrylate, 1,2-propanediol
di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,2-butanediol
di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene
glycol di(meth)acrylate, dimercaptodiethylsulfide di(meth)acrylate,
1,2-ethanedithiol di(meth)acrylate, and/or mixtures thereof.
[0126] Other non-limiting examples of suitable di(meth)acrylate
monomers can include ethylene glycol di(meth)acrylate, 1,3-butylene
glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate,
2,3-dimethyl-1,3-propanediol di(meth)acrylate, 1,6-hexanediol
di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene
glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate,
tetrapropylene glycol di(meth)acrylate, ethoxylated hexanediol
di(meth)acrylate, propoxylated hexanediol di(meth)acrylate,
neopentyl glycol di(meth)acrylate, alkoxylated neopentyl glycol
di(meth)acrylate, hexylene glycol di(meth)acrylate, diethylene
glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate,
thiodiethyleneglycol di(meth)acrylate, trimethylene glycol
di(meth)acrylate, triethylene glycol di(meth)acrylate, alkoxylated
hexanediol di(meth)acrylate, alkoxylated neopentyl glycol
di(meth)acrylate, pentanediol di(meth)acrylate, cyclohexane
dimethanol di(meth)acrylate, and ethoxylated bis-phenol A
di(meth)acrylate and/or mixtures thereof.
[0127] In the preparation of the oligomeric polythiol used in
certain embodiments of the present invention, the reactants (a),
(b), and (c) may all be reacted together simultaneously (as in a
"one pot" process) or mixed together incrementally in various
combinations. For example, compound (a) may be reacted first with
the compound (b) having triple bond functionality as discussed
above in a first reaction vessel to produce a first reaction
product, followed by addition of the compound (c) having at least
two double bonds to the reaction mixture to react with the first
reaction product and yield the oligomeric polythiol of the present
invention (or addition of the first reaction product to a second
reaction vessel containing the compound (c)). As an alternative,
the compound (a) may be reacted first with the compound (c) having
at least two double bonds to produce a first reaction product,
followed by addition of the compound (b) to yield the oligomeric
polythiol. In this embodiment, one may optionally add,
simultaneously with or after compound (b), an additional compound
(c) having at least two double bonds, which may be the same as or
different from that reacted earlier with compound (a) to form the
first reaction product.
[0128] When the compound (a) is combined first with the compound
(c), it is believed that they react via a thiol-ene type reaction
of the SH groups of (a) with double bond groups of (c) although the
inventors do not wish to be bound by this mechanism. Such reactions
may typically take place in the presence of a radical initiator as
mentioned above, or in the presence of a base catalyst,
particularly when the compound (c) comprises a compound having at
least one (meth)acrylate type double bonds. Suitable base catalysts
for use in this reaction can vary widely and can be selected from
those known in the art. Non-limiting examples can include tertiary
amine bases such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and
N,N-dimethylbenzylamine. The amount of base catalyst used can vary
widely, but typically it is present in an amount of from 0.001 to
5.0% by weight of the mixture of (a) and (c).
[0129] In certain embodiments, the thioether functional polythiol
is oligomeric. As used herein, the terms "oligomer" and
"oligomeric" and the like are intended to refer to compounds
prepared by addition polymerization to yield a material having
repeating units and having a number average molecular weight (Mn)
up to 5000, such as up to 2000, such as 200 to 1200. The number
average molecular weight may be determined by gel permeation
chromatography using a polystyrene standard.
[0130] The stoichiometric ratio of the sum of the number of thiol
equivalents of all polythiols present (compound (a)) to the sum of
the number of equivalents of all double bonds present (including
alkyne functionality effective as two double bond equivalents as
discussed above) is greater than 1:1. In non-limiting embodiments,
this ratio can be within the range of from greater than 1:1 to 3:1,
or from 1.01:1 to 3:1, or from 1.01:1 to 2:1, or from 1.05:1 to
2:1, or from 1.1:1 to 1.5:1, or from 1.25:1 to 1.5:1. Any endpoints
within these ranges can also be combined.
[0131] Various methods of reacting polyvinyl ether monomers and one
or more dithiol materials are described in detail in U.S. Pat. No.
6,509,418B1, column 4, line 52 through column 8, line 25, which
disclosure is herein incorporated by reference. Various methods of
reacting allyl sulfide and dimercaptodiethylsulfide are described
in detail in WO 03/042270, page 2, line 16 to page 10, line 7,
which disclosure is incorporated herein by reference. Various
methods for reacting a dithiol and an aliphatic, ring-containing
non-conjugated diene in the presence of free radical initiator are
described in detail in WO/01/66623A1, from page 3, line 19 to page
6, line 11, the disclosure of which is incorporated herein by
reference.
[0132] In reacting the compounds (a) and (c), it may be
advantageous to use one or more free radical initiators.
Non-limiting examples of suitable free radical initiators can
include azo compounds, such as azobis-nitrile compounds such as but
not limited to azo(bis)isobutyronitrile (AIBN); organic peroxides
such as but not limited to benzoyl peroxide and t-butyl peroxide;
inorganic peroxides and similar free-radical generators.
[0133] Alternately, the reaction of compounds (a) and (c) can be
effected by irradiation with ultraviolet light either with or
without a photoinitiating moiety.
[0134] The mixture of (a) and (c) can be reacted for a time period
of from 1 hour to 5 days and at a temperature of from 20.degree. C.
to 100.degree. C. Often, the mixture is heated until a
predetermined theoretical value for SH content is achieved.
[0135] The stoichiometric ratio of the sum of the number of
equivalents of triple bond functional groups in compound (b) to the
sum of the number of equivalents of double bonds in compound (c) is
often within the range of from 0.01:0.99 to 1.00:0, or from
0.10:0.90 to 1.00:0, or from 0.20:0.80 to 1.00:0. Any endpoints
within these ranges can also be combined.
[0136] As noted above the present sulfur-containing compounds can
comprise a polythioether or a polymer comprising at least one
polythioether linkage; that is, --[--CH.sub.2--S--CH.sub.2--]--.
Typical polythioethers have from 8 to 200 of these linkages.
Polythioethers suitable for use in the present invention include
but are not limited to those described in U.S. Pat. Nos. 6,372,849,
6,172,179, and 5,912,319, incorporated by reference herein.
Suitable polythioethers typically have a number average molecular
weight of 150 to 10,000, such as 1,000 to 10,000, 2,000 to 5,000 or
3,000 to 4,000. Any endpoints within these ranges can also be
combined. In some embodiments, the polythioether component will be
terminated with non-reactive groups, such as alkyl, and in other
embodiments will contain reactive groups in terminal or pendant
positions. Typical reactive groups are thiol, hydroxyl, amino,
vinyl, and epoxy. For a polythioether component that contains
reactive functional groups, the average functionality typically
ranges from 2.05 to 3.0, such as from 2.1 to 2.6. A specific
average functionality can be achieved by suitable selection of
reactive ingredients. Examples of suitable polythioethers are
available from PRC-DeSoto International, Inc., in their PERMAPOL
line, such as PERMAPOL P-3.1e and PERMAPOL P-3.
[0137] In certain embodiments, the sulfur-containing compound is
dimercaptodioxaoctane ("DMDO"), and in certain specific embodiments
the sulfur-containing compound is a trimer of DMDO. The trimer can
be prepared as described in the examples below. In yet other
embodiments, the sulfur-containing compound is a dimercaptan
terminated polythioether, such as those described in U.S. patent
application Ser. No. 11/260,553, incorporated by reference
herein.
[0138] The sulfur-containing compound in the present invention can
also comprise a polysulfide. A polysulfide is a polymer that
contains multiple sulfur-sulfur linkages; that is, --[S--S]--, in
the polymer backbone and/or in terminal or pendant positions on the
polymer chain. In certain embodiments, the polysulfide polymers
used according to the present invention have two or more
sulfur-sulfur linkages. Suitable polysulfides are commercially
available from AKZO Nobel under the name THIOPLAST and from Toray
Chemicals under the name THIOKEL. These products are available in a
wide range of molecular weights ranging, for example, from less
than 1100 to over 8000, with molecular weight being the average
molecular weight in grams per mole. Particularly suitable is a
number average molecular weight of 1000 to 4000. The crosslink
density of these products also varies, depending on the amount of
crosslinking agent used. The mercaptan content, that is the "SH"
content, of these products can also vary. In some embodiments, it
may be desired to use a combination of polysulfides to achieve the
desired molecular weight and/or crosslink density in the present
compositions. Different molecular weights and/or crosslink
densities can contribute different characteristics to the
composition. For example, compositions wherein the
sulfur-containing compound comprises more than one polysulfide
polymer, and one of the polysulfide polymers has a molecular weight
of approximately 1000, may have desirable non-crystallization
properties.
[0139] In certain embodiments, the sulfur-containing compound is in
the form of a prepolymer. Such prepolymers can be prepared, for
example, by reacting a thiol with a compound comprising isocyanate
functionality; the thiol can have one or more thiol groups and can
further comprise one or more disulfide linkages. Such prepolymers
can be added to the isocyanate component and/or the amine
component.
[0140] When the second or amine component used in the formation of
the present compositions comprises a sulfur-containing compound,
the relative amount of the amine portion and the sulfur-containing
compound portion can vary depending on the needs of the user. For
example, the ratio of amine to sulfur-containing compound can vary
from 1:99 to 99:1, and the amine component can comprise 20 weight
percent, 30 weight percent, or 35 weight percent sulfur-containing
compound, with weight percent based on the total weight of the
amine component.
[0141] In an embodiment, the coating compositions of the present
invention may further include polyurethane and/or
poly(thio)urethane. It will be appreciated by those skilled in the
art that polyurethane and/or poly(thio)urethane can be formed as a
by-product in the reactions of the present invention. In alternate
embodiments, the polyurethane and/or poly(thio)urethane can be
formed in-situ and/or it can be added to the reaction mixture; a
non-limiting example is an NCO functional prepolymer formed by
reaction of a polyol and a polyisocyanate as disclosed herein. A
non-limiting example of polyurethane formed in-situ may include the
reaction product of polyisocyanate and hydroxyl-functional
material, and a non-limiting example of poly(thio)urethane formed
in-situ may include the reaction product of polyisocyanate and
polythioether or other sulfur-containing compound. Non-limiting
examples of suitable polyisocyanates may include those described
herein. Non-limiting examples of suitable hydroxyl-functional
material may include polyols such as those described herein.
Non-limiting examples of sulfur-containing compounds may include
those described herein. Another example of
polyurethane/poly(thio)urethane formed in-situ may include the
reaction product of hydroxyl functional prepolymer/thiol functional
prepolymer and isocyanate-functional material. Suitable examples of
these reactants may include those described herein.
[0142] The polyurea/polythiourea coating composition of the present
invention may be formulated and applied using various techniques
known in the art. Accordingly, the present invention is further
directed to methods for coating a substrate comprising applying to
at least a portion of the substrate any of the coating compositions
described herein. In an embodiment, conventional spraying
techniques may be used. In this embodiment, the isocyanate
component and amine component may be combined such that the ratio
of equivalents of isocyanate groups to equivalents of amine/thiol
groups is greater than 1 and the isocyanate component and the amine
component can be applied to a substrate at a volume mixing ratio of
1:1; the reaction mixture may be applied to an uncoated or coated
substrate to form a first coating on the uncoated substrate or a
subsequent coating on the coated substrate. When determining the
ratio of equivalents of isocyanate groups to equivalents of
reactive amine/thiol groups, the total amine/thiol groups are taken
into consideration; that is the amine groups from any amine or
amines used in the coating, and the thiol groups from any
sulfur-containing compound used in the coating.
[0143] It will be appreciated that the present compositions are two
component or "2K" compositions, wherein the isocyanate component
and the amine component are kept separate until just prior to
application. Such compositions will be understood as curing under
ambient conditions, although a heated forced air or a heat cure can
be applied to accelerate final cure or to enhance coating
properties such as adhesion. In an embodiment, the sprayable
coating composition may be prepared using a two-component mixing
device. In this embodiment, isocyanate component and amine
component are added to a high pressure impingement mixing device.
The isocyanate component is added to the "A-side" and amine
component is added to the "B-side". The A- and B-side streams are
impinged upon each other and immediately sprayed onto at least a
portion of an uncoated or coated substrate. The isocyanate and the
amine or the amine and sulfur-containing compound react to produce
a coating composition that is cured upon application to the
uncoated or coated substrate. The A- and/or B-side can also be
heated prior to application, such as to a temperature of
140.degree. F. Heating may promote a better viscosity match between
the two components and thus better mixing, but is not necessary for
the curing reaction to occur.
[0144] It is believed that the ratio of equivalents of isocyanate
groups to amine/thiol groups may be selected to control the rate of
cure of the coating composition of the present invention. It has
been found that cure and adhesion advantages may result when
applying the coating in a 1:1 volume ratio wherein the ratio of the
equivalents of isocyanate groups to amine/thiol groups (also known
as the reaction index) is greater than one, such as from 1.01 to
1.10:1, or from 1.03 to 1.10:1, or from 1.05 to 1.08:1 or from 1.01
to 1.4 to 1 or from 1.01 to 1.5, or greater than 1.3 to 1. For
example, good adhesion can be obtained using these ratios over
clearcoats that have low surface functionality after cure, such as
carbamate melamine, hydroxyl melamine, 2K urethane, and
silane-containing clearcoats. The term "1:1 volume ratio" means
that the volume ratio varies by up to 20% for each component, or up
to 10% or up to 5%.
[0145] The rate of reaction of the thiol groups with the isocyanate
can be altered depending on the type of amine or amines used. The
amine co-reactant can function as a catalyst in the
thiol/isocyanate reaction. While the inventors do not wish to be
bound by any mechanism, it is believed that the greater the
basicity of the amine, the faster the cure rate between the thiol
and the isocyanate. Accordingly, the particular amine used and the
amount of the amine used can be altered to adjust the cure rate of
the overall composition. Alternatively, a catalyst can be used to
increase the reaction rate. Suitable catalysts include, for
example, DBU and other tertiary amines.
[0146] In a non-limiting embodiment, a commercially available
mixing device available commercially under the designation GUSMER
VR-H-3000 proportioner fitted with a GUSMER Model GX-7 spray gun
may be used. In this device, pressurized streams of the A- and
B-side components are delivered from two separate chambers and are
impacted or impinged upon each other at high velocity to mix the
two components and form a coating composition, which may be applied
to an uncoated or coated substrate using the spray gun. The mixing
forces experienced by the component streams may depend upon the
volume of each stream entering the mixing chamber per unit time and
the pressure at which the component streams are delivered. A 1:1
volume ratio of the isocyanate and amine/thiol per unit time may
equalize these forces.
[0147] Another suitable application device known in the industry
includes a "static mix tube" applicator. In this device, the
isocyanate component and amine component are each stored in a
separate chamber. As pressure is applied, each of the components is
brought into a mixing tube in a 1:1 ratio by volume. Mixing of the
components is effected by way of a torturous or cork screw pathway
within the tube. The exit end of the tube may have atomization
capability useful in spray application of the reaction mixture.
Alternatively, the fluid reaction mixture may be applied to a
substrate as a bead. A static mix tube applicator is commercially
available from Cammda Corporation.
[0148] The polyurea/polythiourea coating compositions of the
present invention may be applied to a wide variety of substrates.
Accordingly, the present invention is further directed to a
substrate coated with any of the composition described herein.
Non-limiting examples of suitable substrates can include but are
not limited to metal, natural and/or synthetic stone, ceramic,
glass, brick, cement, concrete, cinderblock, wood and composites
and laminates thereof; wallboard, drywall, sheetrock, cement board,
plastic, paper, PVC, roofing materials such as shingles, roofing
composites and laminates, and roofing drywall, styrofoam, plastic
composites, acrylic composites, ballistic composites, asphalt,
fiberglass, soil, gravel and the like. Metals can include but are
not limited to aluminum, cold rolled steel, electrogalvanized
steel, hot dipped galvanized steel, titanium and alloys; plastics
can include but are not limited to TPO, SMC, TPU, polypropylene,
polycarbonate, polyethylene, polyamides (Nylon). The substrates can
be primed metal and/or plastic; that is, an organic or inorganic
layer is applied thereto. Further, the coating compositions of the
present invention can be applied to said substrates to impart one
or more of a wide variety of properties such as but not limited to
corrosion resistance, abrasion resistance, impact damage, flame
and/or heat resistance, chemical resistance, UV light resistance,
structural integrity, ballistic mitigation, blast mitigation, sound
dampening, decoration and the like. In non-limiting examples, the
coating compositions of the present invention can be applied to at
least a portion of a building structure or an article of
manufacture such as but not limited to a vehicle. "Vehicle"
includes but is not limited to civilian, commercial, and military
land-, water-, and air-vehicles, for example, cars, trucks, boats,
ships, submarines, airplanes, helicopters, humvees and tanks. The
article of manufacture can be a building structure. "Building
structure" includes but is not limited to at least a portion of a
structure including residential, commercial and military
structures, for example, roofs, floors, support beams, walls and
the like. As used herein, the term "substrate" may refer to a
surface, either external or internal, on at least a portion of an
article of manufacture or the article of manufacture itself. In an
embodiment, the substrate is a truck bed.
[0149] In an embodiment, the polyurea/polythiourea coating
composition of the present invention may be applied to a carrier
film. The carrier film can be selected from a wide variety of such
materials known in the art. Non-limiting examples of suitable
carrier films may include, but are not limited to thermoplastic
materials, thermosetting materials, metal foils, cellulosic paper,
synthetic papers, and mixtures thereof. As used herein, the term
"thermoplastic material" refers to any material that is capable of
softening or fusing when heated and of solidifying (hardening)
again when cooled. Non-limiting examples of suitable thermoplastic
materials may include polyolefins, polyurethanes, polyesters,
polyamides, polyureas, acrylics, and mixtures thereof. As used
herein, the term "thermosetting material" refers to any material
that becomes permanently rigid after being heated and/or cured.
Non-limiting examples may include polyurethane polymers, polyester
polymers, polyamide polymers, polyurea polymers, polycarbonate
polymers, acrylic polymers, aminoplasts, isocyanates, epoxies,
copolymers thereof, and mixtures thereof.
[0150] As noted above, in certain embodiments, the
polyurea/polythiourea coating compositions of the present invention
may be applied to a bare (e.g., untreated, uncoated) substrate, a
pretreated substrate and/or coated substrate having at least one
other coating. In a non-limiting embodiment, the coating
compositions of the present invention may be applied as part of a
multi-layer coating composite. The first coating applied to a
substrate may be selected from a variety of coating compositions
known in the art for surface coating substrates. Non-limiting
examples may include but are not limited to electrodepositable
film-forming compositions, primer compositions, pigmented or
non-pigmented monocoat compositions, pigmented or non-pigmented
base coat compositions, transparent topcoat compositions,
industrial coating compositions, and the like. In another
non-limiting embodiment, the coating compositions of the present
invention may be applied as part of a multi-layer coating composite
comprising a pretreated substrate and coating layers such as but
not limited to electrocoat, primer, base coat, clear coat, and
combinations thereof. In an embodiment, the clear coat comprises
silane functional groups either before or after crosslinking and
cure.
[0151] In a further embodiment, the polyurea/polythiourea coating
compositions of the present invention can be used in a two-coat
application resulting in a textured surface. A first coat is
applied to an uncoated or coated substrate to produce a smooth,
substantially tack-free layer. The "Tack-Free Method" is used to
determine if the layer is substantially tack-free. The Tack-Free
Method includes spraying the coating composition in one coat onto a
non-adhering plastic sheet to a thickness of from 10 to 15 mil
(254-381 microns). When spraying is complete, an operator, using a
loose fitting, disposable vinyl glove, such as one commercially
available as AMBIDEX Disposable Vinyl Glove by Marigold Industrial,
Norcross Ga., gently touches the surface of the coating. The
coating may be touched more than one time by using a different
fingertip. When the glove tip no longer sticks to, or must be
pulled from, the surface of the layer, the layer is said to be
substantially tack-free. The time beginning from the completion of
spraying until when the coating is substantially tack-free is said
to be the tack time or tack-free time. In a non-limiting
embodiment, the tack-free time and the cure time may be controlled
by balancing levels of various composition components such as the
amount and/or type of amine.
[0152] A second coat may then be applied to the first coating layer
as a texturizing layer or "dust coating". The second coating layer
can be applied by increasing the distance between the
application/mixing device and the coated substrate to form discrete
droplets of the coating composition prior to contacting the coated
substrate thereby forming controlled non-uniformity in the surface
of the second layer. The substantially tack-free first layer of the
coating is at least partially resistant to the second layer; i.e.,
at least partially resistant to coalescence of the droplets of
coating composition sprayed thereon as the second layer or dust
coating such that the droplets adhere to but do not coalesce with
the previous layer(s) to create surface texture. The final coating
layer typically exhibits more surface texture than the first or
previous coating layers. Alternatively, a textured surface may be
achieved by injection during in-mold coating, or by spray coating
the present composition and then rolling a texture onto its
surface. An overall thickness of the coating layers may range from
20 to 1000 mils, or from 40 to 150 mils, or from 60 to 100 mils
(1524-2540 microns), or from 500 to 750 mils. Any of the endpoints
within these ranges can also be combined. In a non-limiting
embodiment, the first layer may be the majority of the total
thickness and the dust coating may be from 15-50 mils (381-1270
microns).
[0153] In various embodiments of the present invention, the "first"
coating layer may comprise one, two, three or more layers; and the
"second" coating layer may be one or more subsequent layers applied
thereover. For example, four polyurea (or polyurea/polythiourea)
layers may be applied, with the fourth layer being the dust coating
and each layer having a thickness of from 15 to 25 mil (381-635
microns). It will be appreciated that these coating layers are
relatively "thick". The coating compositions of the present
invention can also be applied as much thinner layers as well, such
as 0.1 to less the 15 mils, such as 0.1 to 10, 0.5 to 3 or 1 to 2
mils. Any of the endpoints within these ranges can also be
combined. Such layers can be used alone or in conjunction with
other coating layers, such as any of those known in the art or
otherwise described herein. When applied at a sufficient thickness
(e.g. 10 to 1000 mils, such as 100 to 200 mils, or 125 mils+/-10
mils), the present polyurea/polythiourea layer(s) can provide blast
and/or ballistic mitigation. "Blast and/or ballistic mitigation"
means, for example, protection in the event of a close proximity
blast, projectile, or explosion. This protection can include, for
example, protection of a structure or portion of a structure, such
as a building structure, vehicle, aircraft, ship/boat, shipping
container and the like, from collapse and/or destruction,
protection against flying debris and blast fragments, gunshots and
the like.
[0154] In alternate embodiments, the coating layers may comprise
the same or different polyurea/polythiourea coating compositions.
For example, the first layer may be a composition comprising
aliphatic and/or aromatic amine components and/or aliphatic and/or
aromatic polyisocyanate and the second layer may comprise the same
or different combination of aliphatic and/or aromatic amine
components and/or aliphatic and/or aromatic polyisocyanate. Either
or both layers may further comprise any of the sulfur-containing
compounds described herein. "Amine component" in this context means
any amine used in the present coatings. In a further embodiment,
the outermost coating layer may comprise a coating composition that
provides a desired durability. The desired durability may depend
upon the use of the coating composition of the present invention
and/or the substrate to which it may be applied. In an embodiment,
a combination of aliphatic and/or aromatic amine and/or
polyisocyanate may be selected such that the composition of the
outermost layer has substantial durability. For example, the
outermost coating layer may have a durability of 1000 kJ to 6000
kJ, or from 800 hours to 4000 hours, when tested using a
Weatherometer (Atlas Material Testing Solutions) in accordance with
method SAE J1960. In this embodiment, the first layer may be a
polyurea composition comprising polyisocyanate and amine, wherein
at least one of the amine and/or polyisocyanate may comprise an
aromatic moiety, and the second layer may be a polyurea composition
comprising predominantly aliphatic amine and aliphatic
polyisocyanate, with little or no aromaticity; again, either or
both of the layers can further comprise any of the
sulfur-containing compounds described herein.
[0155] The polyurea/polythiourea coating compositions of the
present invention may optionally include materials standard in the
art such as but not limited to fillers, fiberglass, stabilizers,
thickeners, fillers, adhesion promoters, catalysts, colorants,
antioxidants, UV absorbers, hindered amine light stabilizers,
rheology modifiers, flow additives, anti-static agents and other
performance or property modifiers that are well known in the art of
surface coatings, and mixtures thereof. For example, the present
coatings can further comprise flame and/or heat resistant material,
such as any one or more of those disclosed in U.S. application Ser.
No. 11/460,439, hereby incorporated by reference in its entirety.
Fillers can include clay and/or silica, and adhesion promoters can
include amine functional materials, aminosilanes and the like;
examples of fillers and adhesion promoters are further described in
U.S. Publication No. 2006/0046068 and U.S. application Ser. No.
11/591,312, hereby incorporated by reference in their entirety.
These additives can be combined with the isocyanate component, the
amine component, or both. In certain embodiments, the coating may
further comprise small amounts of solvent and in certain
embodiments the coating may be substantially solvent-free.
"Substantially solvent-free" means that the coating may contain a
small amount of solvent, such as 5%, 2%, 1% or less.
[0156] The coatings of the present invention can also include a
colorant. As used herein, the term "colorant" means any substance
that imparts color and/or other opacity and/or other visual effect
to the composition. The colorant can be added to the coating in any
suitable form, such as discrete particles, dispersions, solutions
and/or flakes. A single colorant or a mixture of two or more
colorants can be used in the coatings of the present invention.
[0157] Example colorants include pigments, dyes and tints, such as
those used in the paint industry and/or listed in the Dry Color
Manufacturers Association (DCMA), as well as special effect
compositions. A colorant may include, for example, a finely divided
solid powder that is insoluble but wettable under the conditions of
use. A colorant can be organic or inorganic and can be agglomerated
or non-agglomerated. Colorants can be incorporated into the
coatings by grinding or simple mixing. Colorants can be
incorporated by grinding into the coating by use of a grind
vehicle, such as an acrylic grind vehicle, the use of which will be
familiar to one skilled in the art.
[0158] Example pigments and/or pigment compositions include, but
are not limited to, carbazole dioxazine crude pigment, azo,
monoazo, disazo, naphthol AS, salt type (lakes), benzimidazolone,
condensation, metal complex, isoindolinone, isoindoline and
polycyclic phthalocyanine, quinacridone, perylene, perinone,
diketopyrrolo pyrrole, thioindigo, anthraquinone, indanthrone,
anthrapyrimidine, flavanthrone, pyranthrone, anthanthrone,
dioxazine, triarylcarbonium, quinophthalone pigments, diketo
pyrrolo pyrrole red ("DPPBO red"), titanium dioxide, carbon black,
carbon fiber, graphite, other conductive pigments and/or fillers
and mixtures thereof. The terms "pigment" and "colored filler" can
be used interchangeably.
[0159] Example dyes include, but are not limited to, those that are
solvent and/or aqueous based such as acid dyes, azoic dyes, basic
dyes, direct dyes, disperse dyes, reactive dyes, solvent dyes,
sulfur dyes, mordant dyes, for example, bismuth vanadate,
anthraquinone, perylene, aluminum, quinacridone, thiazole,
thiazine, azo, indigoid, nitro, nitroso, oxazine, phthalocyanine,
quinoline, stilbene, and triphenyl methane.
[0160] Example tints include, but are not limited to, pigments
dispersed in water-based or water miscible carriers such as
AQUA-CHEM 896 commercially available from Degussa, Inc., CHARISMA
COLORANTS and MAXITONER INDUSTRIAL COLORANTS commercially available
from Accurate Dispersions division of Eastman Chemical, Inc.
[0161] As noted above, the colorant can be in the form of a
dispersion including, but not limited to, a nanoparticle
dispersion. Nanoparticle dispersions can include one or more highly
dispersed nanoparticle colorants and/or colorant particles that
produce a desired visible color and/or opacity and/or visual
effect. Nanoparticle dispersions can include colorants such as
pigments or dyes having a particle size of less than 150 nm, such
as less than 70 nm, or less than 30 nm. Nanoparticles can be
produced by milling stock organic or inorganic pigments with
grinding media having a particle size of less than 0.5 mm. Example
nanoparticle dispersions and methods for making them are identified
in U.S. Pat. No. 6,875,800 B2, which is incorporated herein by
reference. Nanoparticle dispersions can also be produced by
crystallization, precipitation, gas phase condensation, and
chemical attrition (i.e., partial dissolution). In order to
minimize re-agglomeration of nanoparticles within the coating, a
dispersion of resin-coated nanoparticles can be used. As used
herein, a "dispersion of resin-coated nanoparticles" refers to a
continuous phase in which is dispersed discreet "composite
microparticles" that comprise a nanoparticle and a resin coating on
the nanoparticle. Example dispersions of resin-coated nanoparticles
and methods for making them are identified in U.S. application Ser.
No. 10/876,031 filed Jun. 24, 2004, which is incorporated herein by
reference, and U.S. Provisional Application No. 60/482,167 filed
Jun. 24, 2003, which is also incorporated herein by reference.
[0162] Example special effect compositions that may be used in the
coating of the present invention include pigments and/or
compositions that produce one or more appearance effects such as
reflectance, pearlescence, metallic sheen, phosphorescence,
fluorescence, photochromism, photosensitivity, thermochromism,
goniochromism and/or color-change. Additional special effect
compositions can provide other perceptible properties, such as
reflectivity, opacity or texture. In a non-limiting embodiment,
special effect compositions can produce a color shift, such that
the color of the coating changes when the coating is viewed at
different angles. Example color effect compositions are identified
in U.S. Pat. No. 6,894,086, incorporated herein by reference.
Additional color effect compositions can include transparent coated
mica and/or synthetic mica, coated silica, coated alumina, a
transparent liquid crystal pigment, a liquid crystal coating,
and/or any composition wherein interference results from a
refractive index differential within the material and not because
of the refractive index differential between the surface of the
material and the air.
[0163] In certain non-limiting embodiments, a photosensitive
composition and/or photochromic composition, which reversibly
alters its color when exposed to one or more light sources, can be
used in the coating of the present invention. Photochromic and/or
photosensitive compositions can be activated by exposure to
radiation of a specified wavelength. When the composition becomes
excited, the molecular structure is changed and the altered
structure exhibits a new color that is different from the original
color of the composition. When the exposure to radiation is
removed, the photochromic and/or photosensitive composition can
return to a state of rest, in which the original color of the
composition returns. In one non-limiting embodiment, the
photochromic and/or photosensitive composition can be colorless in
a non-excited state and exhibit a color in an excited state. Full
color-change can appear within milliseconds to several minutes,
such as from 20 seconds to 60 seconds. Example photochromic and/or
photosensitive compositions include photochromic dyes.
[0164] In a non-limiting embodiment, the photosensitive composition
and/or photochromic composition can be associated with and/or at
least partially bound to, such as by covalent bonding, a polymer
and/or polymeric materials of a polymerizable component. In
contrast to some coatings in which the photosensitive composition
may migrate out of the coating and crystallize into the substrate,
the photosensitive composition and/or photochromic composition
associated with and/or at least partially bound to a polymer and/or
polymerizable component in accordance with a non-limiting
embodiment of the present invention, have minimal migration out of
the coating. Example photosensitive compositions and/or
photochromic compositions and methods for making them are
identified in U.S. application Ser. No. 10/892,919 filed Jul. 16,
2004 and incorporated herein by reference.
[0165] In general, the colorant can be present in the coating
composition in any amount sufficient to impart the desired
property, visual and/or color effect. The colorant may comprise
from 1 to 65 weight percent of the present compositions, such as
from 3 to 40 weight percent or 5 to 35 weight percent, with weight
percent based on the total weight of the compositions.
[0166] In another embodiment, the polyurea/polythiourea coating
compositions of the present invention when applied to a substrate
possesses color that matches the color of an associated substrate.
As used herein, the term "matches" or like terms when referring to
color matching means that the color of the coating composition of
the present invention substantially corresponds to a desired color
or the color of an associated substrate. For instance, when the
substrate for the polyurea coating composition is a portion of a
vehicle, such as a truck bed, the color of the coating
substantially matches that of the associated vehicle body. This can
be visually observed, or confirmed using spectroscopy
equipment.
[0167] The coatings of the present invention may be part of a
multi-layer coating composite comprising a substrate with various
coating layers such as a pretreatment layer, electrocoat, primer,
base coat and clear coat. At least one of the base coat and clear
coat may contain pigment and/or the clear coat may contain an
adhesion promoter and any of these coatings can be one or more of
the coatings described herein. It is believed that the addition of
adhesion promoter to the clear coat, or to its surface, may improve
the adhesion between the clear coat and the coating composition
applied thereover, although the inventors do not wish to be bound
by any mechanism. In this embodiment, the coating composition of
the present invention may be the reaction product of the isocyanate
component and the amine component with a colorant additive. The
coating composition of the present invention containing colorant
may be applied to at least a portion of the article or structure.
The color of the coated article or structure may match the color of
an associated substrate. An "associated substrate" may refer to a
substrate that comprises the article or structure but is not coated
with the coating composition of the present invention or a
substrate that is attached, connected or in close proximity to the
article or structure, but is not coated with the coating
composition of the present invention.
[0168] As used herein, unless otherwise expressly specified, all
numbers such as those expressing values, ranges, amounts or
percentages may be read as if prefaced by the word "about", even if
the term does not expressly appear. Any numerical range recited
herein is intended to include all sub-ranges subsumed therein.
Plural encompasses singular and vice versa. "Including" and like
terms are open ended; that is, they mean "including but not limited
to". For example, while the invention has been described herein
including the claims in terms of "a" polyurea/polythiourea, "an"
isocyanate, "an" amine, "a" sulfur-containing compound, "a"
polythiol, "a" polythioether, "a" polysulfide, "a" catalyst, and
the like, mixtures of all of such things can be used. Also, as used
herein, the term "polymer" is meant to refer to prepolymers,
oligomers and both homopolymers and copolymers; the prefix "poly"
refers to two or more.
EXAMPLES
[0169] The following examples are intended to illustrate the
invention and should not be construed as limiting the invention in
any way.
[0170] In the following examples, unless otherwise stated, the
refractive index and Abbe number were measured on a multiple
wavelength Abbe Refractometer Model DR-M2 manufactured by ATAGO
Co., Ltd.; the refractive index and Abbe number of liquids were
measured in accordance with ASTM-D1218; the refractive index and
Abbe number of solids was measured in accordance with
ASTM-D-542.
[0171] The viscosity was measured using a Brookfield CAP 2000+
Viscometer.
[0172] The SH equivalents were determined using the following
procedure. A sample size (0.1 mg) of the product was combined with
50 mL of tetrahydrofuran (THF)/propylene glycol (80/20) and stirred
at room temperature until the sample was substantially dissolved.
While stirring, 25.0 mL of 0.1 N iodine solution (which was
commercially obtained from Aldrich 31, 8898-1) was added to the
mixture and then allowed to react for a time period of from 5 to 10
minutes. To this mixture was added 2.0 mL concentrated HCl. The
mixture was then titrated potentiometrically with 0.1 N sodium
thiosulfate in the millivolt (mV) mode. A blank value was initially
obtained by titrating 25.0 mL iodine (including 1 mL of
concentrated hydrochloric acid) with sodium thiosulfate in the same
manner as conducted with the product sample.
% SH = ( mls Blank - mls Sample ) .times. ( Normality NA 2 S 2 O 3
) .times. ( 3.307 ) Sample weight , g ##EQU00001##
Example 1
Synthesis of 2/1 (Mol/Mol) Adduct of Dimercaptodiethylsulfide
(DMDS) and Propargylalcohol (PA) (Polythiol H)
[0173] In a glass jar with magnetic stirrer were mixed DMDS from
Nisso Maruzen, Japan, 154.0 g. (1.0 mol) and PA from Aldrich, 28.0
g. (0.5 mol) at room temperature. Then this mixture was heated up
to 60.degree. C. using an oil bath. The mixture was kept at this
temperature while stirring for 30 min. An exothermic reaction
started to take place, leading to an increase in the temperature of
the reaction mixture to 80.degree. C. for a short period of time.
This exothermic reaction was over after 30 minutes and the reaction
temperature went down to 60.degree. C., the temperature of the
heating bath. Radical initiator VAZO.sup.1 64, 50 mg., 275 ppm was
added three times at intervals of 5 hours while the mixture was
stirred at 60.degree. C. The equivalent weight of the product was
181.5 g/equiv (theoretical 182 g/equiv), based on an Mn=363. VAZO
64, 50 mg., 275 ppm was added again and the mixture was heated at
60.degree. C. upon stirring for another 5 hours. The equivalent
weight measurement showed no changes and the reaction was
considered completed. The viscosity of the materials was 258 cPs
(25.degree. C.), nD=1.627, Abbe 36, nE=1.631, Abbe 36. The yield
was quantitative. .sup.1 Available from DuPont.
Example 2
Synthesis of 2/1 (Mol/Mol) Adduct of (DMDS) and 1,3-Diisopropenyl
benzene (DIPEB) (POLYTHIOL B)
[0174] 524.6 g DMDS (3.4 mol) were charged to a glass jar, and the
contents were heated to 60.degree. C. To the jar was slowly added
269.0 g DIPEB (1.7 mol) with mixing. Once the addition of DIPEB was
completed, the jar was placed in an oven heated to 60.degree. C.
for 2 hours. Afterwards, 0.1 g VAZO 52 was dissolved into the
contents of the jar, and the jar was returned to the oven. After 20
hours, the resulting sample was titrated for --SH equivalents and
was found to have an equivalent weight of 145 g/mol. 0.1 g VAZO 52
was dissolved into the reaction mixture, which was then returned to
the oven. Over the course of 8 hours, two additions of 0.2 g VAZO
52 were made, and the reaction mixture kept in the 60.degree. C.
oven over that time frame. 17 hours after the final addition of
VAZO 52 was made, the resulting sample was titrated to an
equivalent weight of 238 g/equiv (theoretical 233 g/equivalent).
The viscosity of the material at 25.degree. C. was measured and
found to be 490 cPs. The yield was quantitative.
Example 3
Synthesis of 2/1 (Mol/Mol) Adduct of POLYTHIOL B and PA (POLYTHIOL
E)
[0175] Polythiol B (prepared according to Example 2) 200.0 g. (0.42
mol) and PA, 11.6 g. (0.21 mol) were mixed at room temperature.
Then this mixture was heated up to 65.degree. C. Radical initiator
VAZO 52, 42 mg, 200 ppm was added three times at intervals of 5
hours while the mixture was stirred at 65.degree. C. The SH
equivalent weight was determined to be 499 g/equiv. The mixture was
heated at 65.degree. C. for another 5 hours and the SH equivalent
weight was measured again, and determined to be 499 g/equiv, based
on an Mn=998. The viscosity of the mixture was 463 cPs (73.degree.
C.), nD=1.620, Abbe 36, nE=1.624, Abbe 35. The yield was
quantitative.
Example 4
Synthesis of 2/1 (Mol/Mol) Adduct of DMDS and 5-Vinyl-2-norbornene
(VNB) (POLYTHIOL V)
[0176] 77 g DMDS (0.5 mol) was charged to a glass jar, and the
contents were heated to 60.degree. C. To this jar was slowly added
30 g VNB (0.25 mol) with mixing, while keeping the temperature of
the mixture .about.60.degree. C. After completion of the addition
the mixture was heated at 60.degree. C. for another 30 min, then
0.2 g VAZO 67 was dissolved into the contents of the jar, and the
jar was heated at 65.degree. C. for 20 hours. The resulting product
was analyzed for SH content by titration with iodine. An SH
equivalent weight of 216 g/equiv (theoretical 214 g/equivalent) was
calculated. The viscosity of the material at 25.degree. C. was
measured and found to be 460 cPs. The product obtained was a
transparent colorless liquid, n.sub.D=1.607, Abbe 39,
n.sub.E=1.610, Abbe 39. The yield was quantitative.
Example 5
Polythiol Blend
[0177] A polythiol blend was prepared by blending Polythiol B
(prepared as described in Example 2) and Polythiol E (prepared as
described in Example 3) in a ratio of 3/2 (w/w) by weight.
Example 6
Dimercaptodioxaoctane (DMDO) Trimer
[0178] A thiol functional resin was prepared as described below:
Triallylcyanurate acid (167.8 g) and DMDO (371.81 g) were combined
and warmed to 65.degree. C. and 0.1416 g of VAZO 67 added. The
reaction was monitored hourly by measuring the thiol equivalent
weight. VAZO 67 (approx 0.15 g) was added after each measurement
until the thiol equivalent weight was greater than 250 meq/g. After
the initial 2 hours the temperature was increased to 85.degree. C.,
and after an additional 2 hours the reaction temperature was
increased to 95.degree. C. The reaction was monitored for a total
of 8 hours. The final material had a measured solids content of 95%
(1 hr, 110.degree. C.), thiol equivalent weight of 257 meq/g and Mw
of 5858 as measured by gel permeation chromatography. The DMDO
trimer thus prepared can be incorporated into a coating according
to the present invention by using the trimer in the amine component
as generally taught herein. Alternatively the DMDO trimer can be
formulated into a prepolymer and used in the isocyanate
component.
Examples 7-12
[0179] An isocyanate-functional polythiourethane for use as the "A"
side in Example 12 was prepared as described below
[0180] A total of 193.6 grams of isophorone diisocyanate, 180 grams
of THIOPLAST G4.sup.2, and 136.8 grams of TERATHANE 650.sup.3, were
added to a suitable reaction vessel equipped with a stirrer,
temperature probe, condenser and a nitrogen cap. The contents of
the flask were mixed well. Then 0.3 grams of dibutyltin dilaurate
were added to the mixture. The contents were slowly heated to
80.degree. C. The contents underwent an exotherm to 112.degree. C.
The reaction was held at 100.degree. C. for 2.5 hours. The
isocyanate equivalent weight of the contents was then measured and
found to be 537. The temperature of the reaction mixture was
lowered to 80.degree. C. Finally, 224 grams of DESMODUR.sup.4
XP2580 and 225 grams of DESMODUR.sup.5 XP2410 were added to the
reaction mixture. The contents of the reactor were cooled and
poured out. The final material had a measured solids of 96%, a
viscosity of Z3, and an isocyanate equivalent weight of 266. .sup.2
Mercaptan-terminated poly-disulfide mixture, available from AKZO
Nobel..sup.3 Polytetramethylene ether glycol, available from
Invista..sup.4 An allophonate of hexamethylene diisocyanate,
available from Bayer Material Science..sup.5 An asymmetric trimer
of hexamethylene diisocyanate, available from Bayer Material
Science.
TABLE-US-00001 percent by Component weight A-side For Example 12
IPDI 16.05 DBTDL 0.003 TERATHANE 650 11.35 AKZO NOBEL G4 14.92
DESMODUR XP2410 28.84 DESMODUR XP2580 28.84
[0181] An isocyanate-functional polyurethane for use as the A side
in Examples 7-11, was prepared as described below
[0182] A total of 1348.9 grams of isophorone diisocyanate (IPDI)
and 1901.5 grams of TERATHANE 650, were added to a suitable
reaction vessel equipped with a stirrer, temperature probe,
condenser and a nitrogen cap. The contents of the flask were mixed
well. Then 0.2 grams of dibutyltin dilaurate (DBTDL) were added to
the mixture. The contents were slowly heated to 80.degree. C. The
contents underwent an exotherm to 112.degree. C. The reaction was
held at 100.degree. C. for 2.5 hours. The isocyanate equivalent
weight of the contents was then measured and found to be 531. The
temperature of the reaction mixture was lowered to 80.degree. C.
Finally, 2490.6 grams of DESMODUR XP2580 and 2490.6 grams of
DESMODUR XP2410 were added to the reaction mixture. The contents of
the reactor were cooled and poured out. The final material had a
measured solids of 98%, a viscosity of Y, and an isocyanate
equivalent weight of 255.8.
TABLE-US-00002 percent by Component weight A-side For Examples 7-11
IPDI 16.4 DBTDL 0.003 TERATHANE 650 23.1 DESMODUR XP2410 30.3
DESMODUR XP2580 30.3
[0183] Pigment grinds were prepared according to the following
table:
TABLE-US-00003 Grind 1 Ingredient Percent by Weight JEFFAMINE
T3000.sup.6 24.0 DESMOPHEN 1220 NH.sup.7 22 BYK-9077.sup.8 0.6
VULCAN XC72.sup.9 1.2 BENTONE 34.sup.10 3 .sup.6Polyoxyalkylene
primary amine of approximately 3000 MW, available from Huntsman
Corporation. .sup.7Amine-functional asparatic acid ester, available
from Bayer Corporation. .sup.8Additive, available from Byk-Chemie.
.sup.9Carbon black pigment, available from Cabot Corporation.
.sup.10Organoclay rheology additive, available from Elementis
Specialities, Inc.
For Grind 1, the ingredients were combined and charged to a Model
HM1.5VSD bead mill (Premier Mill Inc.) using with Mill Mates TZP
Plus grind media (supplied by Zircoa Inc) at 85% mill loading and
ground at a mill speed of 2400 rpm. The grinds were judged to be
complete when the particle size was found to be 7.5 Hegman upon
drawdown on a fineness of grind gauge.
[0184] The "B" side formulations were prepared as shown in the
following table:
TABLE-US-00004 Component percent by weight B-side Ex 7 Ex 8 Ex 9 Ex
10 Ex 11 Ex 12 GRIND 1 50.8 50.8 50.8 50.8 50.8 50.8 JEFFAMINE
T-3000 10 -- -- -- -- -- JEFFLINK 754.sup.11 -- 29.7 17.5 23.1 19.7
29.2 DESMOPHEN 1220 NH 11 8 9 9 9 10 DMDO (95%).sup.12 -- -- -- --
6 -- POLYTHIOL H (from Example 1) 17 -- -- -- -- -- POLYTHIOL V
(from Example 4) -- 9 -- -- -- -- POLYTHIOL B (from Example 2) --
-- 20.2 -- -- -- POLYTHIOL BLEND (from -- -- -- 14.60 -- -- Example
5) P3.1e.sup.13 -- -- -- -- 12 -- CLEARLINK 1000.sup.14 8.7 -- --
-- -- -- CHISORB 353.sup.15 2 2 2 2 2 2 DABCO T-12 (dibutyl tin 0.5
0.5 0.5 0.5 0.5 0.5 dilaurate) ratio of equivalents (Index) 1.100
1.107 1.098 1.101 1.094 1.089 of isocyanate to amine/thiol
.sup.11Alicyclic secondary amine, available from Huntsman
Corporation. .sup.12Available from Sigma-Aldrich, Inc.
.sup.13Polythioether, available from PRC-DeSoto International, Inc.
.sup.14Aliphatic secondary amine, available from Dorf-Ketal
Chemicals, LLC. .sup.15Hindered amine light stabilizer, available
from Chitec Chemical Corporation.
[0185] The B side formulations of the table above were made by
taking Grind 1 and then blending in the balance of the other
materials until well mixed. The B side formulations were charged
into separate canisters and to be paired up with the A side
formulation (in separate canisters) and heated to 140.degree. F. in
an oven for 2-6 hrs prior to spraying to ensure samples were
equilibrated. Polyurea coating compositions were produced by mixing
a 1:1 volume ratio of the A-side components to the B-side
components in a static mix tube applicator device available from
Cammda Corporation and sprayed onto panels.
[0186] Hardness values were determined by charging the A and B side
components into a double-barreled syringe equipped with a static
mix tube and a "Pneumatic applicator" (PC Cox Limited) and
injecting the components at a 1:1 ratio into a mold to form a round
"puck" of approximately 6 cm in diameter and 0.2 cm in thickness.
The hardness of the polyurea coating puck at ambient temperature
was measured on the Shore D scale with a Model 212 Pencil Style
Digital Durometer (Pacific Transducer Corp.) The pucks were then
placed in a 140.degree. F. oven for 1 day and the Shore D hardness
of the coating measured with the puck still inside the oven to
prevent cooling. The pucks were removed from the oven and cooled to
ambient temperature. The hardness was measured again on those pucks
at ambient temperature after being out of the oven for 1 day.
[0187] The following table shows results of characterization of the
resulting coatings:
TABLE-US-00005 Ex 7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 Tack free time
(sec) 75 32 50 70 60 38 Hardness (Shore D) @ 55.2 68.3 53.8 64.2
59.2 64.2 ambient temperature, 1 day ambient cure Hardness (Shore
D) @ -- -- -- -- 61.1 65.1 ambient temperature after 3 days ambient
cure Hardness (Shore D) @ 51.5 67.6 43.6 61.2 -- -- ambient
temperature after 4 days ambient cure Hardness (Shore D) @ 52.8
62.2 44.3 60.5 60.5 67.1 ambient temperature after 7 days ambient
cure Hardness (Shore D) after 26.4 24.4 18.1 23.1 28.1 25.6 7 days
at ambient temperature plus 1 day at 140.degree. F. measure @
140.degree. F. Hardness (Shore D), 7 36.2 55.6 35.8 47.4 55.4 65.4
days at ambient plus 1 day at 140.degree. F., after 1 day ambient
(recovery) measured @ ambient
Example 13
Synthesis of Mercaptan-Capped Polythioether
[0188] A 5 liter 4-neck flask was charged with 2254.49 g (12.37
moles) of dimercaptodioxaoctane (DMDO). The flask was flushed with
nitrogen, the contents were heated to 60.degree. C. and, under
stirring, a solution of 1.61 g (0.008 mole) of radical initiator
Vazo-67 [2,2'-azobis(2-methylbutyronitrile) in 1771.35 g (11.20
moles) of diethylene glycol divinyl ether (DEG-DVE) was added over
a period of 5.5 hr while maintaining the temperature at
60-65.degree. C. The mixture was then stirred at 70.degree. C. for
an additional 1.5 hr. To complete the reaction, nine portions of
Vazo-67 (each 0.901 g, 0.0046 mole) were added at one-hour
intervals while the temperature of the reaction mixture was
maintained at 70.degree. C. The contents were heated at 90.degree.
C. for 2 hr, cooled to 70.degree. C. and evacuated at 10 mmHg for 1
hr to give a faint yellow, liquid polythioether (4025.84 g; Yield:
100%); having an equivalent weight of 1702 and a viscosity of 54
poise (measured at a temperature of about 25.degree. C. and a
pressure of about 760 mm Hg according to ASTM D-2849 .sctn.79-90
using a Brookfield CAP 2000 viscometer).
Example 14
Synthesis of Isocyanate-Capped Polythioether
[0189] A 5 liter 4-neck flask was charged with 1932.62 g (0.59
mole) of the mercaptan-capped polythioether of Example 13, the
reaction flask was evacuated at 1 mmHg for 0.5 hr and vacuum was
released under nitrogen. Rubinate 9433, (1210.44 g, 4.54 moles,
modified diphenylmethane diisocyanate, a Huntsman International
product) was added and mixed for 15 min. Polycat 8 (0.94 g, 0.008
mole, N,N-dimethylcyclohexylamine, a product of Air Products) was
added as a base catalyst. A mild exotherm developed and raised the
reaction temperature to 37.degree. C. Without external heating,
stirring was continued at 37-39.degree. C. for 0.75 hr. Reaction
mixture was heated at 39-50.degree. C. for 2 hr. The mercaptan
equivalent weight of the reaction mixture was 117,660 at this
stage. The reaction mixture was evacuated at 46.degree. C./10 mmHg
for 1 hr. After releasing the vacuum under nitrogen, benzoyl
chloride (1.26 g, 0.009 mole), a stabilizer, was added and stirred
for 10 min. The reaction product was yellow in color; has an NCO
equivalent weight of 415 and a viscosity of 148 poise (measured at
a temperature of about 25.degree. C. and a pressure of about 760 mm
Hg according to ASTM D-2849 .sctn.79-90 using a Brookfield CAP 2000
viscometer).
Example 15
Synthesis of Amine-Capped Polythioether
[0190] A 3 liter 4-neck flask was charged with 1703.46 (1.47 moles)
of Permapol.RTM. L-5534, an epoxy-capped polythioether commercially
available from PRC-DeSoto International, Inc., and 628.52 (2.94
moles) of Ethacure 300, a diamine from Huntsman Inc. The contents
were mixed under vacuum (10 mmHg) for 0.25 hr. Polycat 8 (0.47 g,
0.0037 mole) was added and the mixture was heated at 84-92.degree.
C. for 10 hr. The product was light brown in color and had a
viscosity of 6 poise (measured at a temperature of about 25.degree.
C. and a pressure of about 760 mm Hg according to ASTM D-2849
.sctn.79-90 using a Brookfield CAP 2000 viscometer).
[0191] Whereas particular embodiments of this invention have been
described above for purposes of illustration, it will be evident to
those skilled in the art that numerous variations of the details of
the present invention may be made without departing from the
invention as defined in the appended claims.
* * * * *